SARS-CoV-2 antigen detection in deceased bodies: implications for infection prevention

Background & objectives: High transmissibility of the SARS-CoV-2 has significant implications on healthcare workers’ safety, preservation, handling, transportation and disposal of the deceased bodies. The objective of this study was to detect SARS-CoV-2 antigen in nasopharyngeal samples and its implications in handling and care of COVID-19 deceased bodies. Methods: A study was conducted at a dedicated COVID-19 centre on deceased individuals from April to December 2020. Rapid antigen test (RAT) and reverse transcription (RT)-PCR was compared on all the SARS-CoV-2 positive cadavers recruited in the study. Results: A total of 115 deceased individuals were included in the study. Of these, 79 (68.7%) were male and 36 (31.3%) were female and majority were in the age group of 51-60 yr [31 (27%)]. SARS-CoV-2 antigen test was positive in 32 (27.8%) and negative in 83 (72.1%) individuals. The mean time interval between deaths to the sample collection was 13.2 h with interquartile range of eight to 20 h. Reverse transcription (RT)-PCR was used as the reference test and 24 (20.9%) cases were true positive; 93.6 per cent [95% confidence interval (CI) 88.8-98.4%] sensitivity, 45.2 per cent (95% CI 35.5-55%) specificity, 60.2 per cent (95% CI 50.6-69.8%) positive predictive value and 88.8 per cent (95% CI 82.7-95%) negative predictive value of antigen test was computed. Interpretation & conclusions: SARS-CoV-2 antigen test was positive beyond 19 h in COVID-19 deceased individuals. Antigen test was found to be highly sensitive in the deceased. Patients, suspected of having died due to COVID-19, can be screened by this method. As infectiousness of the virus in the deceased bodies cannot be directly concluded from either the antigen or RT-PCR test, yet possible transmission cannot be completely ruled out. Strict infection control measures need to be followed during the handling and clearance of COVID-19 cadavers.

Rapid antigen test as a tool for the identification of SARS-CoV-2 infection and its potential as a self-testing device

ABSTRACT Background: SARS-CoV-2 virus originated in Wuhan (China) in December (2019) and quickly spread worldwide. Antigen tests are rapid diagnostic tests (RDT) that produce results in 15-30 min and are an important tool for the scale-up of COVID-19 testing. COVID-19 diagnostic tests are authorized for self-testing at home in some countries, including Brazil. Widespread COVID-19 diagnostic testing is required to guide public health policies and control the speed of transmission and economic recovery. Methods: Patients with suspected COVID-19 were recruited at the Hospital da Baleia (Belo Horizonte, Brazil). The SARS-CoV-2 antigen-detecting rapid diagnostic tests were evaluated from June 2020 to June 2021 using saliva, nasal, and nasopharyngeal swab samples from 609 patients. Patient samples were simultaneously tested using a molecular assay (RT-qPCR). Sensitivity, specificity, accuracy, and positive and negative predictive values were determined using the statistical program, MedCalc, and GraphPad Prism 8.0. Results: The antigen-detecting rapid diagnostic tests displayed 98% specificity, 60% sensitivity, 96% positive predictive value, and moderate concordance with RT-qPCR. Substantial agreement was found between the two methods for patients tested < 7 days of symptom onset. Conclusions: Our findings support the use of Ag-RDT as a valuable and safe diagnostic method. Ag-RDT was also demonstrated to be an important triage tool for suspected COVID-19 patients in emergencies. Overall, Ag-RDT is an effective strategy for reducing the spread of SARS-CoV-2 and contributing to COVID-19 control.

Rendimiento diagnóstico de la prueba rápida para la detección del antígeno NS1 y anticuerpos IgM e IgG contra el virus del dengue / Diagnostic performance of the rapid test for the detection of NS1 antigen and IgM and IgG anti-antibodies against dengue virus

Objetivos. Determinar el rendimiento diagnóstico de la prueba rápida SD dengue DUO (Inyecta) para la detección de NS1, IgM e IgG en comparación con la prueba de ELISA. Materiales y métodos. Es una evaluación de prueba diagnóstica que incluyó 286 muestras de suero de pacientes con sintomatología atribuible a dengue de zonas endémicas del Perú. Las muestras se analizaron por ELISA y la prueba rápida SD dengue DUO (Inyecta) para IgM, NS1 e IgG en el Instituto de Investigación Nutricional en Lima. Resultados. La sensibilidad de la prueba rápida fue de 68% para NS1 e IgM, y 86% para IgG, mejorando este parámetro a 75% y 81% para NS1 e IgM, respectivamente, en los tres primeros días. La especificidad para los tres analitos fue mayor a 87%. La concordancia de los resultados obtenidos medidos por el coeficiente Kappa para los tres analitos fue buena y no se encontró reacción cruzada con otros arbovirus. Conclusiones. La prueba rápida SD Dengue DUO permite detectar con una adecuada sensibilidad y especificidad NS1, IgM e IgG. La sensibilidad para IgM y NS1 aumenta cuando se detecta en los tres primeros días de síntomas, por lo que se recomienda su implementación en los centros de primer nivel de atención para un diagnóstico temprano y oportuno.

Objectives . To assess the diagnostic performance of the SD dengue DUO rapid test (Inyecta) for the detection of NS1, IgM and IgG in comparison to the ELISA test. Materials and methods . This is a diagnostic test evaluation that included 286 serum samples from patients with symptomatology attributable to dengue from endemic areas of Peru. The samples were analyzed by ELISA and the SD dengue DUO rapid test (Inyecta) for IgM, NS1 and IgG at the Instituto de Investigación Nutricional in Lima. Results . The sensitivity of the rapid test was 68.0% for NS1 and IgM, and 86.0% for IgG, improving to 75.0% and 81.0% for NS1 and IgM, respectively, during the first three days. The specificity for all three analytes was greater than 87.0%. The concordance of the results, measured by the Kappa coefficient for the three analytes, was good and no cross-reaction with other arboviruses was found. Conclusions . The SD dengue DUO rapid test allows detection of NS1, IgM and IgG with adequate sensitivity and specificity. Sensitivity for IgM and NS1 increases when detected during the first three days of symptoms. Therefore, we recommend its implementation in primary care centers for early and timely diagnosis.

Leptospirosis in central & eastern Uttar Pradesh, an underreported disease: A prospective cross-sectional study

Background & objective: Leptospirosis is a zoonotic disease associated with potentially fatal consequences and a grossly underreported disease in Uttar Pradesh. However, only a few studies are available which report the prevalence of leptospirosis in this State. Hence, this study was undertaken to know the status of the disease in central and eastern Uttar Pradesh. Methods: A total of 143 serum and urine samples were collected from patients with acute febrile illness from July 2017 to March 2019. All the serum samples were tested for Leptospira by rapid IgM antibody card and IgM ELISA and urine samples were tested by real-time polymerase chain reaction (RT-PCR) to detect Leptospira DNA. All positive and 10 per cent negative sera from ELISA and RT-PCR (all rapid test positive were also ELISA positive) were sent to the ICMR-Regional Medical Research Centre, Port Blair for microscopic agglutination test (MAT). Results: Thirty eight (26.6%) out of 143 samples were positive for leptospirosis either by ELISA or RT-PCR. Positive results were eight (6%) by Rapid card, 32 (22%) by IgM ELISA, 10 (7%) by MAT, 10 (7%) by RT-PCR. In MAT, the most common serovar was Lai followed by Hebdomadis, Bangkinang and Pomona. Interpretation & conclusions: Leptospirosis was found to be one of the important causes for acute febrile illness in the central and eastern parts of Uttar Pradesh. The results of the present study suggest that it is necessary to increase diagnostic facility and awareness in clinicians for the screening of leptospirosis in acutely febrile patients to decrease morbidity and mortality associated with this disease.

Development of novel-nanobody-based lateral-flow immunochromatographic strip test for rapid detection of recombinant human interferon α2b / 药物分析学报

Recombinant human interferon α2b(rhIFNα2b)is widely used as an antiviral therapy agent for the treatment of hepatitis B and hepatitis C.The current identification test for rhIFNα2b is complex.In this study,an anti-rhIFNα2b nanobody was discovered and used for the development of a rapid lateral flow strip for the identification of rhIFNα2b.RhIFNα2b was used to immunize an alpaca,which established a phage nanobody library.After five steps of enrichment,the nanobody I22,which specifically bound rhIFNα2b,was isolated and inserted into the prokaryotic expression vector pET28a.After subsequent purification,the physicochemical properties of the nanobody were determined.A semiquantitative detection and rapid identification assay of rhIFNα2b was developed using this novel nanobody.To develop a rapid test,the nanobody I22 was coupled with a colloidal gold to produce lateral-flow test strips.The developed rhIFNα2b detection assay had a limit of detection of 1 μg/mL.The isolation of I22 and successful construction of a lateral-flow immunochromatographic test strip demonstrated the feasibility of performing ligand-binding assays on a lateral-flow test strip using recombinant protein products.The principle of this novel assay is generally applicable for the rapid testing of other com-mercial products,with a great potential for routine use in detecting counterfeit recombinant protein products.

O impacto do GeneXpert® MTB/Rif na detecção da tuberculose e seu padrão espacial em Ribeirão Preto-SP / The impact of GeneXpert® MTB/Rif in the detection of tuberculosis and its spatial pattern in Ribeirão Preto-SP

INTRODUÇÃO: Em 2010 a OMS autorizou o uso do sistema GeneXpert® MTB/RIF para a realização do Teste Rápido Molecular para TB (TRM-TB). Objetivou-se-se analisar o impacto do GeneXpert® MTB/RIF na detecção da TB e da TB multidroga-resistente e seu padrão de distribuição espacial em Ribeirão Preto-SP. MÉTODOS: Estudo ecológico realizado em Ribeirão Preto-SP. A população do estudo foi composta de casos de TB notificados no Sistema de Controle de Pacientes com Tuberculose (TBWeb) no período de 2006 a 2017. A análise descritiva dos casos foi realizada por meio de estatística descritiva dos parâmetros quantitativos através do software IBM SPS Statistics versão 25. Para classificar a tendência temporal e observar o impacto da implementação do TRM-TB, foram utilizadas as metodologias Prais-Winsten e Série Temporal Interrompida (STI) através do software StataSE versão 14 e também a modelagem ARIMA com a finalidade de obter uma previsão da taxa de TB para os próximos anos através do software RStudio. Para identificar os padrões espaciais da doença no município foram empregadas as técnicas de estimador de densidade de Kernel, G e G* e varredura (puramente espacial, variação nas tendências temporais e espaço-temporal). RESULTADOS: A tendência temporal da TB apresentou decréscimo de 18,1%/ano e de 6,9%/ano para em crianças. O Distrito Norte apresentou decréscimo de 6,67%/ano e o distrito Leste crescimento de 17,5%/ano na incidência de TB. A TB resistente, após a implementação do TRM-TB, apresentou aumento de 0,6% por ano. Na maioria dos anos analisados, a cultura é solicitada para menos da metade dos casos de TB. Foi identificado um aumento no número de solicitações de TMR e estacionariedade nas solicitações de baciloscopia. A maior parte dos casos foi diagnóstica por meio de demanda ambulatorial. Com as análises espaciais utilizadas foi observado que os casos e os aglomerados não se formam de maneira aleatória no espaço, verificando-se que a TB é distribuída desigualmente no município. CONCLUSÃO: Apesar da TB resistente não ser um problema no cenário, o estudo evidenciou um crescimento na sua incidência, o que o coloca em estado de alerta. O uso da análise espacial possibilitou a identificação das áreas prioritárias, colocando-as em evidência para ações de vigilância em saúde. Ressalta-se a importância do uso de ferramentas de análise espacial na identificação de áreas que devem ser priorizadas para o controle da TB, sendo necessária maior atenção aos indivíduos que se enquadram no perfil indicado como "de risco" para a doença

INTRODUCTION: In 2010, the WHO authorized the use of the GeneXpert® MTB/RIF system to perform the Molecular Rapid Test for TB (TRM-TB). The objective was to analyze the impact of GeneXpert® MTB/RIF in the detection of TB and multidrug-resistant TB and its spatial distribution pattern in Ribeirão Preto-SP. METHODS: Ecological study carried out in Ribeirão Preto-SP. The study population consisted of TB cases reported in the Tuberculosis Patient Control System (TBWeb) from 2006 to 2017. Descriptive analysis of cases was performed using descriptive statistics of quantitative parameters through the IBM SPS Statistics software version 25. To classify the temporal trend and observe the impact of the TRM-TB implementation, the Prais-Winsten and Interrupted Time Series (STI) methodologies were used through the StataSE software version 14 and also the ARIMA modeling in order to obtain a prediction of the TB rate for the coming years through RStudio software. To identify the spatial patterns of the disease in the city, the techniques of Kernel density estimator, G and G* and scanning (purely spatial, variation in temporal and spatio-temporal trends) were used. RESULTS: The temporal trend of TB showed a decrease of 18.1%/year and of 6.9%/year for children. The Northern District showed a decrease of 6.67%/year and the East District a growth of 17.5%/year in the incidence of TB. Resistant TB, after the implementation of the TRM-TB, increased by 0.6% per year. In most of the years analyzed, culture is requested for less than half of TB cases. An increase in the number of RMT requests and stationarity in smear microscopy requests was identified. Most cases were diagnosed through outpatient demand. With the spatial analysis used, it was observed that cases and clusters do not form randomly in space, verifying that TB is unevenly distributed in the municipality. CONCLUSION: Although resistant TB is not a problem in the scenario, the study showed an increase in its incidence, which puts it on alert. The use of spatial analysis made it possible to identify priority areas, putting them in evidence for health surveillance actions. We emphasize the importance of using spatial analysis tools to identify areas that should be prioritized for TB control, requiring greater attention to individuals who fit the profile indicated as "at risk" for the disease

Technical performance of a lateral flow immunoassay for detection of anti-SARS-CoV-2 IgG in the outpatient follow-up of non-severe cases and at different times after vaccination: comparison with enzyme and chemiluminescent immunoassays

ABSTRACT This study assessed the technical performance of a rapid lateral flow immunochromatographic assay (LFIA) for the detection of anti-SARS-CoV-2 IgG and compared LFIA results with chemiluminescent immunoassay (CLIA) results and an in-house enzyme immunoassay (EIA). To this end, a total of 216 whole blood or serum samples from three groups were analyzed: the first group was composed of 68 true negative cases corresponding to blood bank donors, healthy young volunteers, and eight pediatric patients diagnosed with other coronavirus infections. The serum samples from these participants were obtained and stored in a pre-COVID-19 period, thus they were not expected to have COVID-19. In the second group of true positive cases, we chose to replace natural cases of COVID-19 by 96 participants who were expected to have produced anti-SARS-CoV-2 IgG antibodies 30-60 days after the vaccine booster dose. The serum samples were collected on the same day that LFIA were tested either by EIA or CLIA. The third study group was composed of 52 participants (12 adults and 40 children) who did or did not have anti-SARS-CoV-2 IgG antibodies due to specific clinical scenarios. The 12 adults had been vaccinated more than seven months before LFIA testing, and the 40 children had non-severe COVID-19 diagnosed using RT-PCR during the acute phase of infection. They were referred for outpatient follow-up and during this period the serum samples were collected and tested by CLIA and LFIA. All tests were performed by the same healthcare operator and there was no variation of LFIA results when tests were performed on finger prick whole blood or serum samples, so that results were grouped for analysis. LFIA's sensitivity in detecting anti-SARS-CoV-2 IgG antibodies was 90%, specificity 97.6%, efficiency 93%, PPV 98.3%, NPV 86.6%, and likelihood ratio for a positive or a negative result were 37.5 and 0.01 respectively. There was a good agreement (Kappa index of 0.677) between LFIA results and serological (EIA or CLIA) results. In conclusion, LFIA analyzed in this study showed a good technical performance and agreement with reference serological assays (EIA or CLIA), therefore it can be recommended for use in the outpatient follow-up of non-severe cases of COVID-19 and to assess anti-SARS-CoV-2 IgG antibody production induced by vaccination and the antibodies decrease over time. However, LFIAs should be confirmed by using reference serological assays whenever possible.

Evaluación del desempeño de una prueba rápida para el tamizaje de la infección por Trypanosoma cruzi en pacientes con el virus de la inmunodeficiencia humana / Performance evaluation of a rapid test for the screening of Trypanosoma cruzi infection in patients with human immunodeficiency virus

Resumen Un diagnóstico rápido y seguro de la infección por Trypanosoma cruzi permite la administración inmediata de un tratamiento etiológico específico, en los casos clínicamente manifiestos. En el presente trabajo, en 100 sueros de pacientes con diagnóstico presuntivo de infección por T. cruzi, se evaluó el desempeño de la prueba rápida Chagas Ab Rapid SD Bioline (PDR) para el diagnóstico serológico, se la comparó con el estándar diagnóstico (par serológico) y se la valoró para su empleo en la rutina del laboratorio. La PDR reveló un índice de concordancia muy bueno respecto del estándar diagnóstico (Kappa=0,989 [IC95% 0,965-1,000]) y los parámetros de sensibilidad, especificidad, valores predictivos positivos y negativos revelaron un buen desempeño. El índice de Youden informó un buen rendimiento de la prueba (J=0,98 [IC95% 0,93-1,02]); y en el mismo sentido, tanto la razón de verosimilitud positiva (RV (+)= infinito), como la negativa (RV (-)= 0,02 [IC95% 0,00-0,16]), mostraron aumentada la probabilidad que la enfermedad blanco esté presente o ausente, cuando la técnica así lo determinaba. El empleo de una PDR, por su simpleza y buen desempeño (con resultados disponibles el mismo día) produciría una optimización de recursos, podría realizarse en lugares donde el acceso al diagnóstico es limitado y donde su incorporación no requeriría de una infraestructura importante. Por otro lado, en nuestro caso, podría ser utilizada como segunda prueba, para incrementar la especificidad del diagnóstico serológico de la infección por T. cruzi.

Abstract A quick and safe diagnosis of Trypanosoma cruzi infection allows the immediate etiological treatment in clinically manifested cases. In the present work, the performance of the rapid Chagas Ab Rapid SD Bioline (PDR) test for serological diagnosis was evaluated in 100 sera from patients with a presumptive diagnosis of T. cruzi infection, it was compared with the diagnostic standard (serological pair) and this technique was valued to be used within the laboratory routine. The PDR revealed a very good concordance index with respect to the diagnostic standard (Kappa=0.989 [95% CI 0.965-1.000]) and the parameters of sensitivity, specificity, positive and negative predictive values revealed good performance. The Youden index reported good performance of the diagnostic test (J = 0.98 [95% CI 0.93-1.02]); and in the same sense, both the positive likelihood ratio (RV (+) = infinity), and the negative (RV (-) = 0.02 [95% CI 0.00-0.16]) showed an increased probability whether the target disease was present or absent, when the technique so determined. The use of a PDR, due to its simplicity and good performance (with results available on the same day) would produce an optimization of resources, could be carried out in places where access to the diagnosis is limited and where its incorporation would not require an important infrastructure. On the other hand, in our case, it could be used as a second test, to increase the specificity of the serological diagnosis of T. cruzi infection.

Resumo Um diagnóstico rápido e seguro da infecção pelo Trypanosoma cruzi permite a administração imediata de um tratamento etiológico específico nos casos clinicamente manifestos. No presente trabalho, o desempenho do teste rápido Chagas Ab Rapid SD Bioline (PDR) para o diagnóstico sorológico foi avaliado em 100 soros de pacientes com diagnóstico provável de infecção por T. cruzi, foi comparado com o padrão diagnóstico (par sorológico) e essa técnica foi avaliada para ser utilizada na rotina do laboratório. O PDR revelou um índice de concordância muito bom em relação ao padrão diagnóstico (Kappa=0,989 [IC 95% 0,965-1.000]) e os parâmetros de sensibilidade, especificidade, valores preditivos positivos e negativos revelaram bom desempenho. O índice de Youden informou um bom desempenho do teste diagnóstico (J = 0,98 [IC 95% 0,93-1,02]); e, no mesmo sentido, tanto a razão de verossimilhança positiva (RV (+) = infinito), quanto a negativa (RV (-) = 0,02 [IC 95% 0,00-0,16]), mostraram uma probabilidade aumentada de a doença-alvo estar presente ou ausente, quando a técnica assim o determinar. A utilização de um PDR, pela sua simplicidade e por um bom desempenho (com resultados disponíveis no mesmo dia) produziria uma otimização de recursos, podendo ser realizado em locais onde o acesso ao diagnóstico é limitado, e onde a sua incorporação não exigiria um infraestrutura importante. Por outro lado, no nosso caso, poderia ser utilizado como segundo teste, para aumentar a especificidade do diagnóstico sorológico da infecção pelo T. cruzi.

Performance of an alternative RT-PCR procedure using residual sample from the Panbio™ Ag COVID-19 test

ABSTRACT Introduction: In the current standard of care (SoC) RT-PCR method for COVID-19, the patient's swab was extracted in viral transport media (VTM). For the PanbioTM COVID-19 Ag Rapid Test, the patient swab is flushed out in extraction buffer, of which a small fraction is used for testing, leaving more than half the sample unused. This study was designed to show that RT-PCR results from the residual sample of the PanbioTM COVID-19 Ag Rapid Test (called Novel RT-PCR) are not worse than the SoC RT-PCR result. Methods: The study was performed using (1) dilution series of five patient samples, and (2) 413 patient samples comparing SOC versus Novel RT-PCR results. Results: For the dilution series samples, all tested positive by both methods. The bias between Ct values of Novel RT-PCR and SoC RT-PCR did not exceed 3.00 Ct using primers N1 and N2. A total of 413 COVID symptomatic patients seeking COVID testing were tested, of which 89 patients tested positive and 324 tested negative with SoC RT-PCR. In 324 patients who tested negative with SoC RT-PCR, 323 tested negative with Novel RT-PCR, and one (1) tested positive. Out of 89 who tested positive with SoC RT-PCR, 80 tested positive with the Novel RT-PCR, and nine patients showed a negative test result. The Overall Percent Agreement for the 413 valid patient sample pairs was 97.5 [95% CI 97 to 98]. Conclusion: The study demonstrated that the performance of the Novel RT-PCR method is acceptable compared to the SoC RT-PCR method and can be a useful tool to perform RTPCR without the need for new swab collections.

Time-dependent decay of detectable antibodies against SARS-CoV-2: A comparison of ELISA with two batches of a lateral-flow test

ABSTRACT Background: Large-scale epidemiological studies of seroprevalence of antibodies against SARS-CoV-2 often rely on point-of-care tests that provide immediate results to participants. Yet, little is known on how long rapid tests remain positive after the COVID-19 episode, or how much variability exists across different brands and even among batches of the same test. Methods: In November 2020, we assessed the sensitivity of three tests applied to 133 individuals with a previous positive PCR result between April and October. All subjects provided finger prick blood samples for two batches (A and B) of the Wondfo lateral-flow IgG/IgM test, and dried blood spot samples for the S-UFRJ ELISA test. Results: Overall sensitivity levels were 92.5% (95% CI 86.6-96.3), 63.2% (95% CI 54.4-71.4) and 33.8% (95% CI 25.9-42.5) for the S-UFRJ test, Wondfo A and Wondfo B tests, respectively. There was no evidence of a decline in the positivity of S-UFRJ with time since the diagnosis, but the two Wondfo batches showed sharp reductions to as low as 41.9% and 19.4%, respectively, for subjects with a positive PCR in June or earlier. Positive results for batch B of the rapid test were 35% to 54% lower than for batch A at any given month of diagnosis. Interpretation: Whereas the ELISA test showed high sensitivity and stability of results over the five months of the study, both batches of the rapid test showed substantial declines, with one of the batches consistently showing lower sensitivity levels than the other. ELISA tests based on dried-blood spots are an inexpensive alternative to rapid lateral-flow tests in large-scale epidemiological studies.

Tamización para el virus de la hepatitis C en tres hospitales de Cundinamarca, Colombia / Screening for hepatitis C virus in three hospitals in Cundinamarca, Colombia

Introducción. La infección por el virus de la hepatitis C (VHC) es un problema de salud pública en el mundo. La Organización Mundial de la Salud (OMS) calcula en más de 70 a 100 millones las personas infectadas. La mayoría de ellas, a lo largo del mundo entero, no han sido diagnosticadas y permanecen sin tratamiento. Objetivo. Determinar la prevalencia de anticuerpos contra el VHC en pacientes con factores de riesgo para la infección, en tres hospitales del departamento de Cundinamarca, Colombia, mediante la prueba rápida SD Bioline en sangre capilar, y la confirmación de la infección por la prueba de ARN-PCR en tiempo real (PCR-RT). Metodología. Estudio de tipo observacional descriptivo donde se incluyeron pacientes adultos atendidos en los servicios de consulta externa de los hospitales de La Mesa, Ubaté y Zipaquirá. Se definieron como factores de riesgo para hepatitis C: antecedente transfusional antes de 1996, cirugías mayores (tórax, abdomen, ortopédicas), tatuajes, piercing. Se empleó como prueba rápida el kit comercial SD Bioline HCV (Standard Diagnostics, INC. Corea). Esta prueba contiene una membrana recubierta con antígenos recombinantes del VHC (core, NS3, NS4, NS5). Resultados. Entre enero y octubre de 2018 se tamizaron 1.856 pacientes, 1.531 mujeres (82%) y 325 (18%) hombres, con edad promedio de 45 años y rango de edad de 18 a 89 años. Los principales factores de riesgo identificados fueron los antecedentes de cirugía y las transfusiones antes de 1996. Se detectaron 2 pacientes mujeres positivas, mayores de 50 años, y como factor de riesgo el haber sido sometidas a cirugía mayor y el antecedente transfusional antes de 1996, confirmadas por la técnica de PCR-RT, lo que da una prevalencia global de la infección del 0,1%, pero del 0,05% en las personas con antecedente quirúrgico, 0,25% entre los mayores de 50 años, y 0,6% en los pacientes con antecedente transfusional antes de 1996. Conclusiones. Este estudio realizado en una población seleccionada por factores de riesgo asociados, mostró una prevalencia global de infección por VHC de 0,1%. Nuestros resultados de tamización con prueba rápida en una población seleccionada con factores de riesgo, sugieren que la estrategia de tamización se debe dirigir a personas mayores de 50 años con antecedente transfusional y cirugía mayor.

Introduction. Infection with hepatitis C virus (HCV) is a worldwide public health problem. The World Health Organization (WHO) estimates that more than 70 to 100 million people are infected. Most of them, throughout the world, have not been diagnosed and remain untreated. Objective. To determine the prevalence of antibodies against HCV in patients with risk factors for infection, in three hospitals in the department of Cundinamarca, Colombia, by means of the rapid SD Bioline test in capillary blood, and the confirmation of infection by real-time PCR (RT-PCR). Methodology. Adult patients treated in the outpatient services of the La Mesa, Ubaté and Zipaquirá hospitals. Risk factors for hepatitis C were defined as: transfusion history before 1996, major surgeries (chest, abdomen, orthopedic), tattoos, and piercing. The commercial SD Bioline HCV kit (Standard Diagnostics, INC. Korea) was used as the rapid test. This kit contains a membrane coated with recombinant HCV antigens (core, NS3, NS4, NS5). Results. Between January and October 2018, 1,856 patients were screened, 1,531 women (82%) and 325 (18%) men, with an average age of 45 years and an age range of 18 to 89 years. The main risk factors identified were a history of surgery and transfusions before 1996. Two positive female patients were detected, older than 50 years, and as a risk factor, having undergone major surgery and a history of transfusion before 1996, confirmed by the RT-PCR assay, which gives a global prevalence of infection of 0.1%, but of 0.05% in people with surgery history, 0.25% among those over 50 years of age, and 0.6% in patients with a transfusion history before 1996. Conclusions. This study, carried out in a population selected for associated risk factors, showed an overall prevalence of HCV infection of 0.1%. Our results suggest that screening with a rapid test in a selected population with risk factors should be directed at people over 50 years of age with a history of transfusion and major surgery.

Evaluation of a rapid diagnostic test for the detection of Streptococcus pyogenes in invasive infections / Evaluación de una prueba diagnóstica rápida para la detección de Streptococcus pyogenes en infecciones invasivas

Abstract Invasive Streptococcus pyogenes diseases represent the most severe form of infection produced by this microorganism. Early diagnosis and treatment are important, due to its potential severity. Etiological confirmation of invasive infection is performed by culture, which takes between 18 and 48 h. We tested a rapid immunochromatographic assay directly from clinical samples from normally sterile sites and positive blood culture bottles when pos-itive cocci chains were observed by Gram staining. Eighty samples were analyzed. The rapid test was positive in 35 samples: in 34 of them S. pyogenes was confirmed by culture. The immunochromatographic method showed 97.1% sensitivity and 97.8% specificity. The strept A® immunochromatographic rapid test allows to obtain reliable results in less than 10min and is accessible to any microbiology laboratory. This study demonstrates the potential use of a rapid immunochromatographic method directly from clinical samples and positive blood cultures.

Resumen La enfermedad invasiva por Streptococcus pyogenes representa la forma más grave de infección producida por este microorganismo y requiere un rápido diagnóstico, a fin de instaurar un tratamiento adecuado. La confirmación etiológica de esta infección se realiza por cultivo, lo que puede llevar entre 18 y 48 h. En este estudio ensayamos una prueba inmunocromatográfica rápida directamente de muestras clínicas de sitios normalmente estériles y de botellas de hemocultivos positivos cuando la coloración de Gram evidenció cocos gram positivos en cadena. Se analizaron 80 muestras. La prueba rápida fue positiva en 35 muestras: en 34 de ellas se confirmó la presencia de S. pyogenes por cultivo. La sensibilidad y la especificidad de la prueba fueron del 97,1 y el 97,8%, respectivamente. La prueba inmunocromatográfica rápida monteBIO Strep A® permite obtener resultados confiables en menos de 10 min y es accesible para cualquier laboratorio de microbiología. Este estudio demuestra la utilidad de dicha prueba para ser practicada directamente en muestras clínicas y botellas de hemocultivos positivos.

Diagnostic performance of COVID-19 serology assays

@#Introduction: The World Health Organization (WHO) declared COVID-19 outbreak as a world pandemic on 12th March 2020. Diagnosis of suspected cases is confirmed by nucleic acid assays with real-time PCR, using respiratory samples. Serology tests are comparatively easier to perform, but their utility may be limited by the performance and the fact that antibodies appear later during the disease course. We aimed to describe the performance data on serological assays for COVID-19. Materials and Methods: A review of multiple reports and kit inserts on the diagnostic performance of rapid tests from various manufacturers that are commercially available were performed. Only preliminary data are available currently. Results: From a total of nine rapid detection test (RDT) kits, three kits offer total antibody detection, while six kits offer combination SARS-CoV-2 IgM and IgG detection in two separate test lines. All kits are based on colloidal gold-labeled immunochromatography principle and one-step method with results obtained within 15 minutes, using whole blood, serum or plasma samples. The sensitivity for both IgM and IgG tests ranges between 72.7% and 100%, while specificity ranges between 98.7% to 100%. Two immunochromatography using nasopharyngeal or throat swab for detection of COVID-19 specific antigen are also reviewed. Conclusions: There is much to determine regarding the value of serological testing in COVID-19 diagnosis and monitoring. More comprehensive evaluations of their performance are rapidly underway. The use of serology methods requires appropriate interpretations of the results and understanding the strengths and limitations of such tests.

Comparación del rendimiento diagnóstico clínico versus la prueba rápida durante dos temporadas de influenza / Comparison of clinical diagnostic performance versus the rapid test during two seasons of influenza

Resumen Introducción Una reflexión de la pandemia de influenza en 2009 es la prioridad de la prescripción temprana de los antivirales, previniendo el uso injustificado de antibióticos. Objetivo: Describir la sintomatología que se asocia más al diagnóstico definitivo de influenza y comparar el rendimiento del diagnóstico clínico contra el diagnóstico arrojado por la prueba rápida. Material y métodos Estudio retrospectivo, transversal, descriptivo y analítico. Se incluyeron pacientes con diagnóstico presuntivo de influenza admitidos en el Servicio de Urgencias del Hospital Español de México en dos temporadas consecutivas que van de octubre de 2016 a marzo de 2017 y de octubre de 2017 a marzo de 2018. Se formaron dos grupos: pacientes con PCR positiva (grupo A) y pacientes con PCR negativa (grupo B). Resultados Se obtuvo un total de 857 pacientes con diagnóstico presuntivo clínico de influenza, de los cuales 537 se confirmaron con influenza por PCR (grupo A) y 320 fueron negativos para dicha prueba (grupo B). El síndrome conformado por tos, fiebre, rinorrea y artralgias tiene una especificidad de 92.2% en comparación con la prueba rápida de 99.1%. Conclusiones El síndrome caracterizado por tos, fiebre, rinorrea, artralgias presentes durante los meses invernales tiene una alta especificidad para infección por el virus de la influenza.

Abstract Introduction One of the reflections of the influenza pandemic in 2009 is the priority of the early prescription of antivirals, preventing the unjustified use of antibiotics. Objective: To describe the symptomatology that is associated more with the definitive diagnosis of Influenza and to compare the performance of the clinical diagnosis against the diagnosis thrown by the rapid test. Material and methods A retrospective, cross-sectional, descriptive and analytical study. All patients with presumptive diagnosis of Influenza admitted to the Emergency Service of the Hospital Español de Mexico were included in two consecutive seasons from October 2016 to March 2017 and October 2017 to March 2018. Two groups were formed of the included patients: patients with positive PCR (group A) and patients with negative PCR (group B). Results A total of 857 patients with presumptive clinical diagnosis of influenza were obtained, of whom 537 were confirmed with Influenza by PCR (group A) and 320 were negative for the test (group B). The syndrome consisting of cough, fever, rhinorrhea and arthralgia has a specificity of 92.2% compared to the rapid test of 99.1%. Conclusions The syndrome characterized by cough, fever, rhinorrhea, arthralgia present during winter months has a high specificity for an infection by the Influenza virus.

Percepção dos profissionais para implantação do teste rápido para HIV e Sífilis na Rede Cegonha / The professional's perception for the implantation of the rapid test for HIV and Syphilis in Rede Cegonha / La percepción de los profesionales para la implantación de la prueba rápida para VIH y Sífilis en la Rede Cegonha

O artigo investiga a avaliação dos profissionais da Atenção Primária (AP) sobre a implantação do aconselhamento e do teste rápido de HIV e Sífilis na Rede Cegonha (RC). Trata-se de um estudo qualitativo, descritivo e exploratório, no qual foram realizadas 13 entrevistas semiestruturadas com profissionais da AP, analisadas a partir da análise temática. Os resultados apontam a falta de conhecimento dos profissionais em relação às inovações da RC na AP. Os profissionais receberam capacitações referentes à testagem rápida, porém o matriciamento foi considerado inexistente. A solicitação do teste rápido das gestantes é realizada de forma compulsória. O aconselhamento, quando presente, é restrito ao pré-teste de HIV e outras Infecções Sexualmente Transmissíveis (IST), tendo caráter informativo, desconsiderando as especificidades da gestação. Indica-se a necessidade de se refletir sobre a autonomia das mulheres durante o pré-natal e o aconselhamento, espaço este que pode ser repensado como um momento de fortalecimento e acolhimento.

The article investigates the evaluation of the Primary Health Care (PHC) professionals about the implementation of the HIV and Syphilis rapid test in the care policy for pregnant women (CPPW). This is a qualitative, descriptive and exploratory study, which were conducted 13 semi-structured interviews with professionals, and analyzed from the thematic analysis. The results show a lack of knowledge of professionals about the innovations of CPPW in PHC. The professional received trainings for the rapid test, but the matricial support, with longitudinal supervision with specialized professionals, was considered inexistent. The test request of the pregnant women is released of compulsory form. Counseling is restricted to the pre-test of HIV and other Sexually Transmitted Infections (STIs), and just informative, disregarding the specifics of pregnancy. It is necessary to rethink the women's autonomy during the prenatal care and counseling and to construction these spaces as a moment of empowerment and welcoming.

El artículo investiga la evaluación de los profesionales de la Atención Primaria (AP) en relación a la implantación del asesoramiento y prueba rápida del VIH y Sífilis en la red de atención a las gestantes. El presente estudio es cualitativo, descriptivo y exploratorio, en el cual se realizaron 13 entrevitas semiestructuradas con los profesionales de la AP, analizadas a partir del análisis temático. Los resultados señalan la falta de conocimiento de los profesionales en relación a las innovaciones del RC en la AP. Los profesionales recibieron capacitaciones referentas a la prueba rápida del VIH, pero la supervisión longitudinal de los casos fue considerado inexistente. La solicitud de la prueba rápida de VIH y otras Infecciones Sexualmente Transmissibles (ISTs) a las gestantes se realiza de forma obligatoria. El asesoramiento, cuando presente, se limita al pre-test del VIH y otras ISTs, teniendo carácter informativo, desconsiderando las especificidades de la gestación. Se indica que es necesario repensar la autonomía de las mujeres durante el prenatal y el asesoramiento, para que este sea un espacio de empoderamiento y acogida para las mujeres.

Evaluación de la prueba rápida VIRAPID® Hidatidosis / Evaluation of the VIRAPID® Hydatidosis rapid test / Avaliação do teste rápido VIRAPID® Hidatidose

El diagnóstico presuntivo de la equinococosis quística (EQ) se basa en estudios clínicos e imagenológicos, en particular aquellos que aplican ultrasonido, en datos epidemiológicos, y se confirma con la serología específica. En las zonas endémicas rurales, donde los procedimientos imagenológicos no siempre se encuentran disponibles, al igual que la serología convencional debido a la falta de laboratorios suficientemente equipados, las pruebas de diagnóstico rápido (TDRs) pueden ser una herramienta de gran utilidad. Se evaluó aquí la precisión diagnóstica de VIRAPID® Hidatidosis (Vircell, España), comparado con dos métodos comerciales usados frecuentemente en este laboratorio, para el diagnóstico de la Hidatidosis: HIDATEST (Laboratorio Lemos, Argentina) y ELISA IgG Echinococcus (Vircell, España). El análisis se realizó sobre 224 muestras de igual número de pacientes; 48 (21,4%) pertenecían a pacientes con quistes probablemente hidatídicos, mientras que 10 (4,5%) a pacientes con quistes no parasitarios. Se agregaron a ellos, 166 (74,1%) muestras que resultaron previamente negativas en la casuística de este laboratorio. Para los tres métodos antes mencionados, la concordancia entre los resultados obtenidos fue evaluada por el estadístico Kappa, donde en todos los casos pudo apreciarse un grado de acuerdo casi excelente. La sensibilidad y especificidad de VIRAPID fueron de 94,1%, 98,9%, ELISA 90,6%, 99,4% e HIDATEST 96,0%, 96,2%, respectivamente. Los TDRs para hidatidosis pueden ser útiles en aquellos entornos con escasos recursos para establecer la certeza diagnóstica. La prueba VIRAPID® Hidatidosis demostró tener un muy buen rendimiento, aunque sería interesante evaluar la sensibilidad del test en presencia de quistes inactivos, lo cual, se supone podría plantear problemas para el diagnóstico.

The presumptive diagnosis of cystic echinococcosis (EQ) is based on clinical and imaging studies, particularly those that apply Ultrasound, in epidemiological data, and is confirmed with specific serology. In rural endemic areas, where imaging procedures are not always available, as with conventional serology due to the lack of sufficiently equipped laboratories, rapid diagnostic tests (TDRs) can be a very useful tool. The diagnostic accuracy of VIRAPID® Hydatidosis (Vircell, Spain) was evaluated here, compared with two commercial methods frequently used in the Laboratory, for the diagnosis of Hydatidosis: HIDATEST (Laboratorio Lemos, Argentina) and ELISA IgG Echinococcus (Vircell, Spain). The analysis was performed on 224 samples from the same number of patients; 48 (21.44%) belonged to patients with probable hydatid cysts, while 10 (4.46%) belonged to patients with non-parasitic cysts. A total of 166 (74.10%) samples that were previously negative in the casuistry of our Laboratory were added. For the three methods mentioned above, the agreement between the results obtained was evaluated by the Kappa statistics, where in all the cases an almost excellent degree of agreement could be appreciated. The Sensitivity and Specificity of VIRAPID® was 94.12%, 98.88%, ELISA 90.57%, 99.44% and HIDATEST 96.00%, 96.17%, respectively. TDRs for hydatidosis may be useful in settings with limited resources to establish diagnostic certainty. The VIRAPID® test showed a very good performance, although it would be interesting to evaluate the sensitivity of the test in the presence of inactive cysts, which can pose problems for the diagnosis.

O diagnóstico presuntivo de equinococose cística (EQ) baseia em estudos clínicos e de imagem, em particular aqueles que aplicam ultrasom, em dados epidemiológicos, e é confirmado com a sorologia específica. Em áreas endêmicas rurais, onde os procedimentos de imagens nem sempre estão disponíveis, como acontece com a sorologia convencional devido à falta de laboratórios suficientemente equipamentados, os testes de diagnóstico rápido (TDRs) podem ser uma ferramenta de grande utilidade. A precisão do diagnóstico de VIRapid® hidatidose (Vircell, Espanha) foi avaliada aqui, em comparação com dois métodos comerciais frequentemente usados neste laboratório, para o diagnóstico de Hidatidose: HIDATEST (Laboratório Lemos, Argentina) e ELISA IgG Echinococcus (Vircell, Espanha). A análise foi realizada em 224 amostras do mesmo número de pacientes; 48 (21,4%) pertenciam a pacientes com cistos provavelmente hidatídicos, enquanto 10 (4,5%) pertenciam a pacientes com cistos não parasitários. Adicionaram-se a eles 166 (74,1%) amostras que resultaram previamente negativas na casuística desse Laboratório. Para os três métodos citados acima, a concordância entre os resultados obtidos foi avaliada pela estatística Kappa, onde em todos os casos um grau de concordância quase excelente pôde ser apreciado. Sensibilidade e especificidade de VIRapid® foi de 94,1%, 98,9%, ELISA 90,6%, 99,4% e HIDATEST, 96,0% e 92,6%, respectivamente. Os TDRs para hidatidose podem ser úteis em ambientes com recursos limitados para estabelecer a certeza diagnóstica. O teste VIRAPID® Hidatidose mostrou ter desempenho muito bom, apesar de que seria interessante avaliar a sensibilidade do teste em presença de cistos inativos, o que se supõe pode causar problemas para o diagnóstico.

Comparación del algoritmo nuevo con el algoritmo convencional para diagnóstico de VIH en Bolivia / Comparison of new algorithm with the conventional algorithm for diagnosis of HIV in Bolivia / Comparação do novo algoritmo com o algoritmo convencional para o diagnóstico do HIV na Bolívia

En Bolivia, el algoritmo diagnóstico convencional para VIH utiliza como prueba confirmatoria el Western blot; debido a dificultades con el costo, tiempo y centralización del diagnóstico confirmatorio, el Programa Nacional ITS/VIH/SIDA-HV propuso un algoritmo nuevo que utiliza solo dos pruebas rápidas y ELISA Ag/Ac. Sesenta muestras de suero fueron procesadas con ambos algoritmos y se determinó el resultado verdadero de las muestras de acuerdo con ambos algoritmos y la carga viral. La sensibilidad, especificidad, valores predictivos, índice Kappa y chi-cuadrado de Pearson fueron calculados. El algoritmo convencional reportó: sensibilidad 96,3%, especificidad 100%, valor predictivo positivo 100% y valor predictivo negativo 97% el algoritmo nuevo presentó sensibilidad, especificidad, valores predictivos positivo y negativo del 100%. El índice Kappa fue 0,966 y chi-cuadrado de Pearson 56,078 con p<0,01; es así que el grado de concordancia entre ambos algoritmos es "muy bueno" y estadísticamente significativo. Aunque el número de muestras procesadas en este estudio fue reducido, el algoritmo nuevo parece ser mejor que el convencional debido a que acorta el tiempo de detección de VIH y reporta resultados iguales a la carga viral.

In Bolivia, the conventional diagnostic algorithm for HIV uses Western blot as a confirmatory test. Due to difficulties with cost, time and centralization of the confirmatory diagnosis, the National STI/HIV/AIDS-HV Program proposed a new algorithm, which uses only two rapid tests and ELISA Ag/Ac. A total of 60 serum samples were processed with both algorithms and the true result of the samples was determined according to the results of both algorithms and viral load. Sensitivity, specificity, predictive values, Kappa and chi-square Pearson index were determined. The conventional algorithm reported sensitivity of 96,3%, specificity of 100%, positive predictive value of 100 % and negative predictive value of 97%. The new algorithm presented sensitivity, specificity, positive and negative predictive values of 100%. The Kappa index was 0.966 and chi-square Pearson 56.078 with p <0.01, so the degree of agreement between both algorithms is "very good" and statistically significant. Although the number of samples processed in the present work was reduced, the new algorithm seems to be better than the conventional algorithm because it shortens the period in the detection of HIV and reports results equal to the viral load.

Na Bolívia, o algoritmo de diagnóstico convencional para HIV usa como teste de confirmação o Western blot; devido a dificuldades com custo, tempo e centralização do diagnóstico de confirmação, o Programa Nacional de ITS/HIV/AIDS-HV propôs um algoritmo que usa apenas dois testes rápidos e ELISA Ag/Ac. Foram processadas 60 amostras de soro com ambos os algoritmos e o resultado verdadeiro das amostras foi determinado de acordo com os algoritmos e a carga viral. A sensibilidade, especificidade, valores preditivos, índice de Kappa e qui-quadrado de Pearson foram calculados. O algoritmo convencional reportou: sensibilidade 96,3%, especificidade 100%, valor preditivo positivo 100% e valor preditivo negativo 97%, o novo algoritmo apresentou sensibilidade, especificidade, valores preditivos positivo e negativo de 100%. O índice Kappa foi 0.966 e qui-quadrado de Pearson 56.078 com p<0.01, de modo que o grau de concordância entre os algoritmos é "muito bom" e estatisticamente significativo. Embora o número de amostras processadas neste estudo tenha sido pequeno, o novo algoritmo parece ser melhor do que o convencional porque reduz o tempo de detecção do HIV e relata resultados iguais à carga viral.

Establishment of time-resolved fluorescence immunochromatographic assay for detection of carbohydrate antigen 19-9 / 生物工程学报

To establish a time-resolved fluorescence immunochromatographic assay for quantitative determination of carbohydrate antigen 19-9 (CA19-9) in serum, we prepared CA19-9 test strips by integrating double-antibody sandwich method and fluorescence immunochromatography technique. Carboxy fluorescent microspheres and nitrocellulose membrane were used as carriers for labeling and coating CA19-9 pairing antibodies. We optimized the process by adjusting the amount of labeling and coating antibody. According to the linear range, lowest detection limit and precision, We evaluated the time-resolved fluorescence immunochromatographic assay of CA19-9. When the amount of labeled antibody was 80 μg for 20 μL fluorescent microspheres, and the concentration of coated antibody on the test line was 1.5 mg/mL, the optimal reaction time was 15 minutes. Assay linear range was 12.5 to 800 U/mL and the minimum detection limit was 6.32 U/mL. The Within-run and between-run coefficient of variation were less than 15%. Average recovery rate was 101%. By detecting 50 clinical samples in parallel with Roche electrochemical luminescence detection kit, correlation coefficient was 0.980 6. The experiment, initially established a fluorescence immunochromatographic detection method to quantitative detection of serum CA19-9, which has a good clinical application prospect.

Validation of the Dual-path Platform chromatographic immunoassay (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis

BACKGROUND Visceral leishmaniasis is a major public health challenge in South America, and dogs are its main urban reservoir. OBJECTIVE Validation of the canine Dual-path Platform immunoassay for canine visceral leishmaniasis (DPP® CVL) for a sample set composed of 1446 dogs from different Brazilian endemic areas. METHODS A well-defined reference standard by means of parasitological culture, immunohistochemistry, and histopathology was used. Animals were classified as asymptomatic, oligosymptomatic, or symptomatic. Sensitivity and specificity were assessed as a single set and in clinical groups. A reproducibility assessment of the tests was conducted using the Kappa (κ) index at three different laboratories (A, B, and C). FINDINGS Overall, 89% sensitivity and 70% specificity were obtained for the entire sample set. Analysis of the clinical groups showed a gradual decrease in the sensitivity and an increase in the specificity with the reduction of clinical signs in the dogs that were assessed, reaching a sensitivity of 75% (42.8-94.5%) among asymptomatic dogs and lower specificity of 56% (46.2-66.3%) among symptomatic dogs. Inter-laboratory agreement was substantial (κAB= 0.778; κAC= 0.645; κCB= 0.711). MAIN CONCLUSIONS The test performance is somewhat dependent on canine symptomatology, but such influence was less evident than in previous studies. Favourable results for sensitivity and specificity can be obtained even in asymptomatic animals; however, caution is needed in these evaluations, and the results suggest that the immunochromatographic test may be further improved for better investigation in asymptomatic dogs. The results obtained confirm the usefulness of DPP® CVL for application in serological surveys.

Narrativas sobre risco e culpa entre usuários e usuárias de um serviço especializado em infecções por HIV: implicações para o cuidado em saúde sexual / Narratives about risk and guilt among patients of a specialized HIV infection service: implications for care in sexual health

Resumo O objetivo deste estudo é compreender como se articulam percepções sobre HIV e aids em narrativas de usuários e usuárias do Sistema de Saúde, trazendo elementos qualitativos que demonstram a importância do aconselhamento em saúde sexual. Foram entrevistados nove usuárias e usuários de um serviço de saúde especializado (CTA) em Porto Alegre, no momento da procura pelo Teste Rápido para HIV, sífilis e hepatites B e C. As narrativas geraram dois eixos de compreensão: Risco/Promiscuidade e Culpa/Responsabilização. Estes eixos sintetizaram algumas das inúmeras possibilidades de significação frente à necessidade de realização do teste de HIV. Os elementos promiscuidade, risco, culpa e responsabilização se compunham a partir de diferentes marcadores sociais, envolvendo experiências sociais que se articulavam com o discurso biomédico epidemiológico. Neste contexto, o aconselhamento se apresenta como um espaço potente para desconstruir significações essencialistas e noções estereotipadas de risco. Este estudo mostra que as narrativas reiteram entendimentos de sexualidade como dimensão individualizada, indicando a necessidade de propostas de trabalho em saúde pela via da singularidade. Considera-se que análises qualitativas centradas na experiência de usuários(as) são estratégicas num projeto de promoção de saúde sexual como processo coletivo.

Abstract The objective of this study is to understand how perceptions about HIV and AIDS are articulated in narratives of male and female patients of the Public Health System, with qualitative elements that demonstrate the importance of sexual health counseling. Nine male and female patients of a specialized health service (CTA) were interviewed in Porto Alegre when they visited the CTA for the HIV, Syphilis and Hepatitis B and C Rapid Test. The narratives generated two understanding axes: Risk/Promiscuity and Guilt/Accountability. These axes synthesized some of the innumerable possibilities of meaning in relation to the need to perform the HIV test. The elements promiscuity, risk, guilt and accountability were composed of different social markers, involving social experiences that were articulated with the epidemiological biomedical discourse. In this context, counseling represents a powerful space to deconstruct essentialist meanings and stereotyped notions of risk. This study shows that the narratives reaffirm the understanding of sexuality as an individualized dimension, which indicates the need for health work proposals on singularity. Qualitative analyses focused on the patients' experience are strategic measures in a project to promote sexual health as a collective process.