Diagnostic performance evaluation of hepatitis B e antigen rapid diagnostic tests in Malawi.

BACKGROUND: The World Health Organization (WHO) has targeted a reduction in viral hepatitis-related mortality by 65% and incidence by 90% by 2030, necessitating enhanced hepatitis B treatment and prevention programmes in low- and middle-income countries. Hepatitis B e antigen (HBeAg) status is used in the assessment of eligibility for antiviral treatment and for prevention of mother-to-child transmission (PMTCT). Accordingly, the WHO has classified HBeAg rapid diagnostic tests (RDTs) as essential medical devices. METHODS: We assessed the performance characteristics of three commercially available HBeAg RDTs (SD Bioline, Alere, South Africa; Creative Diagnostics, USA; and Biopanda Reagents, UK) in two hepatitis B surface antigen-positive cohorts in Blantyre, Malawi: participants of a community study (n = 100) and hospitalised patients with cirrhosis or hepatocellular carcinoma (n = 94). Two investigators, blinded to the reference test result, independently assessed each assay. We used an enzyme-linked immunoassay (Monolisa HBeAg, Bio-Rad, France) as a reference test and quantified HBeAg concentration using dilutions of the WHO HBeAg standard. We related the findings to HBV DNA levels, and evaluated treatment eligibility using the TREAT-B score. RESULTS: Among 194 HBsAg positive patients, median age was 37 years, 42% were femaleand 26% were HIV co-infected. HBeAg prevalence was 47/194 (24%). The three RDTs showed diagnostic sensitivity of 28% (95% CI 16-43), 53% (38-68) and 72% (57-84) and specificity of 96-100% for detection of HBeAg. Overall inter-rater agreement κ statistic was high at 0.9-1.0. Sensitivity for identifying patients at the threshold where antiviral treatment is recommended for PMTCT, with HBV DNA > 200,000 IU/ml (39/194; 20%), was 22, 49 and 54% respectively. Using the RDTs in place of the reference HBeAg assay resulted in 3/43 (9%), 5/43 (12%) and 8/43 (19%) of patients meeting the TREAT-B treatment criteria being misclassified as ineligible for treatment. A relationship between HBeAg concentration and HBeAg detection by RDT was observed. A minimum HBeAg concentration of 2.2-3.1 log10IU/ml was required to yield a reactive RDT. CONCLUSIONS: Commercially available HBeAg RDTs lack sufficient sensitivity to accurately classify hepatitis B patients in Malawi. This has implications for hepatitis B public health programs in sub-Saharan Africa. Alternative diagnostic assays are recommended.

The new IVD Regulation 2017/746: a case study at a large university hospital laboratory in Belgium demonstrates the need for clarification on the degrees of freedom laboratories have to use lab-developed tests to improve patient care.

Objectives: The new European In Vitro Diagnostic (IVD) Regulation 2017/746 (IVDR) restricts the use of lab-developed tests (LDT) after 26th May 2022. There are no data on the impact of the IVDR on laboratories in the European Union. Methods: Laboratory tests performed in UZ Leuven were divided in four groups: core laboratory, immunology, special chemistry, and molecular microbiology testing. Each test was classified as Conformité Européenne (CE)-IVD, modified/off-label CE-IVD, commercial Research Use Only (RUO) or LDT. Each matrix was considered a separate test. Results: We found that 97.6% of the more than 11.5 million results/year were generated with a CE-IVD method. Of the 922 different laboratory tests, however, only 41.8% were CE-IVD, 10.8% modified/off-label CE-IVD, 0.3% RUO, and 47.1% LDT. Off-label CE-IVD was mainly used to test alternative matrices not covered by the claim of the manufacturer (e.g., pleural or peritoneal fluid). LDTs were mainly used for special chemistry, flow cytometry, and molecular testing. Excluding flow cytometry, the main reasons for the use of 377 LDTs were lack of a CE-IVD method (71.9%), analytical requirements (14.3%), and the fact the LDT was in use before CE-IVD available (11.9%). Conclusions: While the large majority of results (97.6%) were generated with a CE-IVD method, only 41.8% of laboratory tests were CE-IVD. There is currently no alternative on the market for 71.5% of the 537 LDTs performed in our laboratory which do not fall within the scope of the current IVD directive (IVDD). Compliance with the IVDR will require a major investment of time and effort.

[Genome detection of dermatophytes : Current findings from the external quality assessment test]. / Genomnachweis von Dermatophyten : Aktuelle Erkenntnisse aus dem Ringversuch.

In addition to morphological diagnostics, molecular methods have become available for the diagnosis of suspected dermatophytoses. Since March 2016, INSTAND e. V., in cooperation with the National Reference Laboratory for Dermatophytes, has provided an external quality assessment (EQA) test for the genome detection of dermatophytes twice a year. More than half of the participants used commercial kits for the analysis of the samples. All kits with a high level of accuracy correctly determined the presence of Trichophyton rubrum or no dermatophytes. In species diagnostics beyond Trichophyton rubrum there are large differences between the kits. These are examined in more detail based on clinical studies and the results of the EQA test.

[A study on clinical application of a novel reagent detecting toxigenic strains of Clostridium difficile].

Objective: To evaluate the performances of a "ready-to-use" liquid chromogenic medium for detecting toxigenic strains of C. difficile from stool specimens, by comparing with the reference method of combined GeneXpert detection with MALDI-TOF MS identification. Methods: This study was a clinical application research. A total of 322 stool specimens from patients with diarrhea in Henan Provincial People's Hospital were detected by using this liquid chromogenic mediumor by combination of GeneXpert and MALDI-TOF MS identification after CCFA culture from March to November 2017. The reference method was combined GeneXpert detection with MALDI-TOF MS identification. Data were analyzed with kappa analysis by use of SPSS 13.0. In this study, the limit of detection and anti-interference capability of chromogenic medium were determined with standard strains. Results: This assay had a sensitivity of 92.86% (52/56), a specificity of 96.99% (258/266), a positive predictive value of 86.67% (52/60), and a negative predictive value of 98.47% (258/262). Furthermore, this assay was well consistent with the reference method (kappa=0.874, P<0.01). The limit of detection of this assay was 10(3) CFU/ml for toxigenic strain of ATCC9689, and there was no interference by non-toxigenic strain of ATCC43593 or Clostridium perfringens (ATCC13124) even.When the concentration of ATCC9689 was as low as 0.5 McFarland. Conclusions: It is worth expanding clinical research for this "ready-to-use" chromogenic medium and preparing for its popularization in primary medical institutions, due to its similar performance to the reference method for detecting toxigenic strains of C. difficile, simple operation and no need of anaerobic condition.

[Proposal for a diagnostic approach to long COVID]. / Propuesta de abordaje diagnóstico del COVID persistente.

The objective of this communication is to provide a proposal for a diagnostic approach to persistent COVID based on the various current etiopathogenic theories and to serve as a guide on how to start the diagnostic process in a patient affected by this syndrome according to the prevailing symptomatology and the basic studies and of extension that can be requested and even assisted by commercial kits that would help a better diagnosis.

La presente comunicación tiene como objetivo aportar una propuesta de abordaje diagnóstico del COVID persistente con base en las diversas teorías etiopatogénicas actuales, así como servir de guía para iniciar el proceso diagnóstico en un paciente afectado por este síndrome, acorde a la sintomatología prevaleciente y a los estudios básicos y de extensión que se pueden solicitar, e incluso auxiliados por pruebas comerciales que ayudarían a un mejor diagnóstico.

La trazabilidad en las mediciones del laboratorio clínico: impacto en la calidad y seguridad del paciente / Traceability in clinical laboratory measurements: impact on quality and patient safety

Las mediciones confiables, trazables metrológicamente y comparables proporcionan la base racional para la evaluación de la calidad de un resultado y el fortalecimiento de las redes de laboratorios clínicos, lo cual permite mejorar la calidad de atención y la seguridad del paciente. En este documento se revisan los principios básicos que deben seguirse para garantizar la trazabilidad de las mediciones del laboratorio clínico, las ventajas de utilizar métodos trazables, el impacto de no hacerlo, y se discuten las principales limitaciones para relacionar las mediciones con los estándares de medición de referencia apropiados

Reliable, metrologically traceable, and comparable measurements provide the rationale for evaluating the quality of a result and strengthening clinical laboratory networks, thereby improving quality of care and patient safety. This document reviews the basic principles that must be followed to ensure the traceability of clinical laboratory results, the advantages of using traceable methods, the impact of not doing so, and the main limitations in relating measurements to appropriate reference standards

Estudio de terreno del reactivo ß pre-ß lipoproteina para el pesquisaje de lipoproteínas

La determinación de lipoproteínas en suero constituye una valoración de interés para el pesquisaje de las hiperlipoproteinemias. Es muy importante contar con un método rápido, sencillo y con un reactivo confiable que asegure dicha valoración. Se presentan los resultados logrados en pruebas de terreno en la provincia Habana con el reactivo ß pre-ß lipoproteína producido en la Empresa de Productos Biológicos "Carlos J. Finlay" y se comparan con un juego de reactivos para la determinación de colesterol con el propósito de analizar su correlación; los resultados obtenidos son satisfactorios. El coeficiente de correlación fue de 0,9997.

Determination of serum lipoproteins is an interesting assessment for the investigation of hyperlipoproteinemia. It is very important to count on a fast and simple method, and with a reliable reagent, to secure such assessment. Here the authors present the results obtained in field tests in Havana province, with the tested ß pre-ß lipoprotein reagent, produced at the "Carlos J. Finlay" biological products enterprise, and these results are compared with a reagent kit for cholesterol determination, with the aim for analysing their correlation. The outcomes were satisfactory. The correlation rate was 0,9997.

Estabilidad a largo plazo del juego de reactivos para la determinación de hemoglobina en sangre

Se estudió la estabilidad a largo plazo del juego de reactivos para la determinación de hemoglobina en sangre, basado en el comportamiento de la estabilidad física y química de los componentes del juego durante 1 año, así como también el ensayo funcional de éstos. Se estudió además el reactivo de trabajo durante 15 d. Un análisis estadístico de los resultados demostró que el juego de reactivos es estable durante los tiempos de estudio, almacenado a una temperatura de 2 a 8 EC.

The long term stability of the reagents kit to determine hemoglobin in blood, based on the physical and chemical stability of the components of the kit during a year, as well as their functional assay, were studied. The working resgent was also studied for 15 days. A statistical analysis of the results showed that the reagents kit is stable during the time under study, stored at a temperature from 2 to 8 EC.

Industrialização e avaliação do método de Western blotting - WB Tp-IgG - como confirmatório na sorologia da sífilis / Industrialization and evaluation of Western blotting method - WB Tp-IgG - as confirmatory for syphilis serology

A sífilis adquirida e a congênita continuam aumentando e preocupando as autoridades sanitárias do mundo, ao verem que as metas estabelecidas para o seu controle estão longe de serem atingidas. Apesar dos esforços feitos na descoberta de novas ferramentas para o diagnóstico e monitoramento da sífilis, vemos um despreparo muito grande, principalmente entre os laboratoristas, em processar corretamente os reagentes disponíveis e melhor selecionar aqueles que apresentem qualidade para serem usados na rotina do laboratório. O que constatamos neste estudo é um espelho da realidade do diagnóstico da sífilis e mostra a dificuldade que os clínicos enfrentam ao receberem um laudo do laboratório. Trabalhando em colaboração com diferentes serviços e grupos de pesquisa, selecionamos aqueles que trabalhavam com: gestantes atendidas no pré-natal, doadores de sangue, pacientes infectados pelo HIV e pacientes de laboratório clínico e fizemos um estudo crítico da sorologia utilizada em cada serviço. Verificamos discrepância dos resultados obtidos nos testes não-treponêmicos VDRL e RPR, principalmente entre os soros de baixa reatividade, e nos treponêmicos FTA-abs, TPHA e ELISA. Decidimos aplicar o método de Western blotting e analisar o seu comportamento em todas as amostras de soros ensaiadas. Para obtenção de resultados reprodutíveis, fizemos a industrialização do método e formatamos um reagente na forma de um kit diagnóstico, WB Tp-IgG, que pudesse ser facilmente utilizado e interpretado. Os resultados obtidos mostraram que o WB Tp-IgG pode ser utilizado como método confirmatório da sífilis, substituindo o FTA-abs, tradicionalmente recomendado para essa finalidade e que pudesse fazer parte de uma proposta de algoritmo para o diagnóstico sorológico da sífilis.

Acquired and congenital syphilis have been increased and worried the worldwide health authorities, mainly because the WHO targets for syphilis control are far from to be held. Much effort had been made for development of new tools to be used in syphilis diagnosis and following up, however we noticed a lack of ability of laboratory workers in the correctly choosing and using the reagents in laboratory routine. In this study what we observed were the reality of syphilis diagnosis and the difficulties that physicians have in how to procedure when they received the results from the laboratory. Working in collaboration with different settings and research groups we choose some of them that attend pregnant women, blood donors, HIV patients and patients from clinical laboratory. With these group individuals we made a critical study of the serology methods used in each one. We verified high level of discordant results between nontreponemal tests VDRL and RPR, mainly in serum samples with low reactivity and between treponemal tests FTA-abs, TPHA and ELISA, in all services. To obtain reproducibility of the results we made the industrialization of the method and set up a reagent as a kit diagnosis, easily to performer. Appling the western blotting method we evaluated the performance of the test in all sera samples assayed. The results showed that the WB Tp-IgG can be useful as confirmatory test for syphilis, replacing FTA-abs, traditionally recommended for this and that could be included in algorithm propose for serological diagnosis of syphilis.