Serologic profiling of D variants in donor routine: unveiling the impact on false-negative results and alloimmunization.

The high number of D variants can lead to the unnecessary use of Rh immune globulin, overuse of D- RBC units, and anti-D allommunization. D variant prevalence varies among ethnic groups, and knowledge of the main variants present in a specific population, their behavior in serologic tests, and their impact on clinical practice is crucial to define the best serologic tests for routine use. The present study aimed to explore the serologic profile of D variants and to determine which variants are most associated with false-negative D typing results and alloimmunization. Donor samples were selected in two study periods. During the first period, D typing was performed on a semi-automated instrument in microplates, and weak D tests were conducted in tube or gel tests. In the second period, D typing was carried out using an automated instrument with microplates, and weak D tests were performed in solid phase. Samples from patients typed as D+ with anti-D were also selected. All samples were characterized by molecular testing. A total of 37 RHD variants were identified. Discrepancies and atypical reactivity without anti-D formation were observed in 83.4 percent of the samples, discrepant D typing results between donations were seen in 12.3 percent, and D+ patients with anti-D comprised 4.3 percent. DAR1.2 was the most prevalent variant. Weak D type 38 was responsible for 75 percent of discrepant samples, followed by weak D type 11, predominantly detected by solid phase. Among the D variants related to alloimmunization, DIVa was the most prevalent, which was not recognized by serologic testing; the same was true for DIIIc. The results highlight the importance of selecting tests for donor screening capable of detecting weak D types 38 and 11, especially in populations where these variants are more prevalent. In pre-transfusion testing, it is crucial that D typing reagents demonstrate weak reactivity with DAR variants; having a serologic strategy to recognize DIVa and DIIIc is also valuable.

Íleo meconial y falsos negativos del resultado de tripsina inmunorreactiva en una niña portadora de fibrosis quística / Meconium Ileus and false negative immunoreactive trypsine results in a cystic fibrosis carrier infant / Íleo meconial e resultados falso-negativos de tripsina imunorreativa em uma menina com fibrose cística

Introducción: la fibrosis quística (FQ) es una enfermedad genética, multisistémica, caracterizada por la disfunción de las glándulas de secreción exocrina secundaria a la mutación de una proteína transmembrana que actúa como canal de cloro. La inclusión de su búsqueda en el Sistema Nacional de Pesquisa Neonatal (SNPN) determinó un gran impacto sobre la morbimortalidad de esta enfermedad, permitiendo un diagnóstico y tratamiento precoz. El íleo meconial (IM) es la manifestación más precoz de la enfermedad, ocurriendo en un 10% a 18% de los pacientes. Objetivo: describir una forma de presentación precoz de FQ con resultado de pesquisa neonatal normal. Caso clínico: 18 meses. Sexo femenino; 33 semanas de edad gestacional. Retraso en la expulsión del meconio. Al tercer día de vida íleo meconial con oclusión intestinal, vólvulo de intestino medio y necrosis intestinal. Se realiza resección quirúrgica. Tripsina inmunorreactiva (TIR) normal a los 7 y 23 días de vida. No se solicita proteína asociada a la pancreatitis (PAP). Desnutrición crónica, bronquiolitis grave a los 3 meses, neumonías virales a los 7 y 11 meses. Ingreso con diagnóstico de neumonía aguda comunitaria con insuficiencia respiratoria. Test del sudor alterado en dos oportunidades. Elastasa pancreática insuficiente. Se aísla Staphylococcus aureus y Pseudomonas aeruginosa en exudado nasal y de secreciones respiratorias. Estudio genético: mutación Delta F508. Con diagnóstico de FQ se inició abordaje multidisciplinario, tratamiento y derivación al centro especializado. Conclusiones: la existencia de IM puede dar falsos negativos en el valor de la TIR, siendo necesaria la dosificación de la PAP. El pronóstico de estos pacientes va a depender de un diagnóstico precoz y el manejo terapéutico oportuno en centros especializados.

Introduction: cystic fibrosis (CF) is a genetic, multisystemic disease, characterized by dysfunction of the exocrine secretion glands secondary to the mutation of a transmembrane protein that acts as a chloride channel. Including its research by the National Neonatal Screening System (SNPN) caused a great impact on the morbidity and mortality of this disease, enabling early diagnosis and treatment. Meconium ileus (MI) is the earliest manifestation of the disease, occurring in 10% to 18% of patients. Objective: to describe a form of early presentation of CF with normal neonatal screening results. Clinical case: 18 months. Female, 33 weeks gestational age. Delay in the expulsion of meconium. On the third day of life, meconium ileus with intestinal obstruction, midgut volvulus and intestinal necrosis. Surgical resection is performed. Trypsin immunoreactive (TIR) normal at 7 and 23 days of age. Pancreatitis-associated protein (PAP) is not requested. Chronic malnutrition, severe bronchiolitis at 3 months, viral pneumonia at 7 and 11 months. Admission with a diagnosis of acute community pneumonia with respiratory failure. Sweat test altered on two occasions. Insufficient pancreatic elastase. Staphylococcus aureus and Pseudomonas aeruginosa were isolated in nasal exudate and respiratory secretions. Genetic study: Delta F508 mutation. With the CF diagnosis, a multidisciplinary approach, treatment and referral to a specialized center began. Conclusions: the existence of MI can provide false negatives in the IRR value, making PAP dosage necessary. The prognosis of these patients will depend on early diagnosis and timely therapeutic management at specialized centers.

Introdução: a fibrose cística (FC) é uma doença genética, multissistêmica, caracterizada pela disfunção das glândulas secretoras exócrinas secundária à mutação de uma proteína transmembrana que age como canal de cloreto. A inclusão da sua pesquisa no Sistema Nacional de Triagem Neonatal (SNPN) determinou grande impacto na morbimortalidade desta doença, permitindo diagnóstico e tratamento precoces. O íleo meconial (IM) é a manifestação mais precoce da doença, ocorrendo em 10 a 18% dos pacientes. Objetivo: descrever uma forma de apresentação precoce da FC com resultados normais de triagem neonatal. Caso clínico: 18 meses. Sexo feminino. 33 semanas de idade gestacional. Atraso na expulsão do mecônio. No terceiro dia de vida, íleo meconial com obstrução intestinal, vólvulo de intestino médio e necrose intestinal. A ressecção cirúrgica é realizada. Imunorreativo à tripsina (TIR) normal aos 7 e 23 dias de vida. A proteína associada à pancreatite (PAP) não é solicitada. Desnutrição crônica, bronquiolite grave aos 3 meses, pneumonia viral aos 7 e11 meses. Internação com diagnóstico de pneumonia comunitária aguda com insuficiência respiratória. Teste do suor alterado em duas ocasiões. Elastase pancreática insuficiente. Staphylococcus aureus e Pseudomonas aeruginosa foram isolados em exsudato nasal e secreções respiratórias. Estudo genético: mutação Delta F508. Com o diagnóstico de FC iniciou-se abordagem multidisciplinar, tratamento e encaminhamento para centro especializado. Conclusões: a existência de IM pode dar falsos negativos no valor da TIR, tornando necessária a dosagem de PAP. O prognóstico destes pacientes dependerá do diagnóstico precoce e do manejo terapêutico oportuno em centros especializados.

Rates of False-Negative Screening in Prostate Specific Antigen Secondary to 5-Alpha Reductase Inhibitor Usage: A Quality-Improvement Initiative.

PURPOSE: Patients often take 5-alpha reductase inhibitors (5-ARIs) for the management of benign prostatic hyperplasia. However, 5-ARIs can decrease prostate specific antigen (PSA) by approximately half and therefore may lead to false negative PSA tests. We investigated false-screening rates in men on 5-ARIs undergoing PSA testing and whether ordering physicians noticed false negative findings. MATERIALS AND METHODS: A single institution, retrospective study was conducted on patients with a PSA value documented between 2014 and 2017. Patient demographics, PSA results, 5-ARI usage, and providing clinician characteristics were collected. Published normal PSA values were used to determine PSA test positivity; values for those on 5-ARIs were doubled. RESULTS: A total of 29,131 men were included. 1,654 (5.7%) were prescribed 5-ARIs at least 12 months prior to PSA evaluation. 118 men (7.1%) had a value that would be positive if corrected for 5-ARI usage, 33 (27.9%) of which had no indication that the provider had noted this. There was no effect on rates of false negative values if the PSA was ordered by a different provider than the one who prescribed the 5-ARI (p = 0.837). However, if the provider who ordered the PSA test was an urologist, the likelihood that a false negative value would be identified was lower (p=0.001). CONCLUSIONS: More than a quarter of men with false negative tests were missed. This occurred more often when the ordering provider was not an urologist. An educational opportunity exists to improve the quality of PSA testing by preventing false negative tests.

Nucleocapsid (N) Gene Mutations of SARS-CoV-2 Can Affect Real-Time RT-PCR Diagnostic and Impact False-Negative Results.

The current COVID-19 pandemic demands massive testing by Real-time RT-PCR (Reverse Transcription Polymerase Chain Reaction), which is considered the gold standard diagnostic test for the detection of the SARS-CoV-2 virus. However, the virus continues to evolve with mutations that lead to phenotypic alterations as higher transmissibility, pathogenicity or vaccine evasion. Another big issue are mutations in the annealing sites of primers and probes of RT-PCR diagnostic kits leading to false-negative results. Therefore, here we identify mutations in the N (Nucleocapsid) gene that affects the use of the GeneFinder COVID-19 Plus RealAmp Kit. We sequenced SARS-CoV-2 genomes from 17 positive samples with no N gene detection but with RDRP (RNA-dependent RNA polymerase) and E (Envelope) genes detection, and observed a set of three different mutations affecting the N detection: a deletion of 18 nucleotides (Del28877-28894), a substitution of GGG to AAC (28881-28883) and a frameshift mutation caused by deletion (Del28877-28878). The last one cause a deletion of six AAs (amino acids) located in the central intrinsic disorder region at protein level. We also found this mutation in 99 of the 14,346 sequenced samples by the Sao Paulo state Network for Pandemic Alert of Emerging SARS-CoV-2 variants, demonstrating the circulation of the mutation in Sao Paulo, Brazil. Continuous monitoring and characterization of mutations affecting the annealing sites of primers and probes by genomic surveillance programs are necessary to maintain the effectiveness of the diagnosis of COVID-19.

Common Pitfalls in the Interpretation of Endocrine Tests.

Endocrine tests are the cornerstone of diagnosing multiple diseases that primary care physicians are frequently faced with. Some of these tests can be affected by situations that affect the proper interpretation, leading to incorrect diagnoses and unnecessary treatment, such as the interference of biotin with thyroid function test, falsely elevated prolactin values in presence of macroprolactinemia or falsely normal due to the "hook effect" in macroprolactinomas. Recognizing these situations is essential for the clinician to make an adequate interpretation of these tests as well as an accurate diagnosis that guarantees the best outcomes for the patient.

[Meta-analysis of diagnostic tests for the detection of COVID-19]. / Metaanálisis de pruebas diagnósticas para la detección de COVID-19.

BACKGROUND: COVID-19 disease emerged at the end of 2019 and it started to be considered a pandemic at the beginning of 2020. The reference methodology for the COVID-19 diagnosis is the RT-qPCR. OBJECTIVE: It was assessed the sensitivity and specificity of molecular test kits found on the list of tests of the Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE, Institute for Epidemiologic Diagnosis and Reference). MATERIAL AND METHODS: By using the PubMed and the Google Scholar platforms, a search was carried out for articles, out of which 14 were selected, retrieving the number of samples analyzed and their status (positive or negative), according to the molecular reference method, the name of the test kit used, as well as the characteristics and results obtained, expressed as true positives, false negatives, true negatives and false positives. Sensitivity and specificity of 8 kits were calculated, with compilations of the OpenEpi, version 3.01, statistical calculators, by using the Wilson score with a 95% confidence interval. RESULTS: The sensitivity and specificity results for the kits were greater than 90%. CONCLUSIONS: Tests evaluated allow the detection of presence or absence of virus, but they can be affected by conditions during the stages of the method.

INTRODUCCIÓN: la enfermedad COVID-19 surgió a finales de 2019 y se empezó a considerar pandemia a principios de 2020. La metodología de referencia para su diagnóstico es la prueba RT-qPCR. OBJETIVO: se evalúo la sensibilidad y la especificidad de kits de pruebas moleculares que se encuentran en la lista de pruebas del Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE). MATERIAL Y MÉTODOS: a partir del uso de las plataformas PubMed y Google Scholar se realizó una búsqueda de artículos, de los cuales se seleccionaron 14 y se recuperó el número de muestras analizadas y su estado (positivo o negativo) según el método molecular de referencia, el nombre del kit de prueba utilizado, así como las características y los resultados obtenidos, expresados como verdaderos positivos, falsos negativos, verdaderos negativos y falsos positivos. Se calculó la sensibilidad y la especificidad de ocho kits con la compilación de calculadoras estadísticas OpenEpi versión 3.01, mediante el método de puntos de Wilson con un intervalo de confianza de 95%. RESULTADOS: los kits evaluados tuvieron una sensibilidad y una especificidad superior al 90%. CONCLUSIONES: las pruebas permiten detectar la presencia o ausencia del virus, pero pueden verse afectadas por condiciones durante las etapas del método.

A cost of illness comparison for toxigenic Clostridioides difficile diagnosis algorithms in developing countries.

BACKGROUND: Availability of several commercial tests with different Clostridioides difficile targets contributes to uncertainty and controversies around the optimal diagnostic algorithm. While numerous studies have estimated the financial impact of C. difficile infection, models to guide testing strategies decisions in developing countries, where economic value significantly impacts clinical practice, are currently not available. AIM: To determine the cost of illness of different C. difficile infection (CDI) diagnostic strategies in developing countries. METHODS: Cost-comparison analysis was performed to compare eleven different algorithms of CDI diagnosis. The basis of calculation was a hypothetical cohort of 1000 adult inpatients suspected of CDI. We analyzed turnaround time of test results (i.e., time from taking sample to results emission), test performance (i.e., sensitivity and specificity) and testing costs. Patients were divided in true positive, false positive, true negative and false negative in order to integrate test performance and economics effects. Additional medical costs were calculated: costs of hygiene, medication, length of stay and intensive care unit costs, based on a Brazilian University Hospital costs. CDI prevalence was considered 22.64%. FINDINGS: From laboratory-assisted tests, simultaneous glutamate dehydrogenase (GDH) and toxin A/B rapid immunoassay arbitrated by nucleic acid amplification test (NAAT) presented the lowest cost of illness (450,038.70 USD), whereas standalone NAAT had the highest (523,709.55 USD). Empirical diagnosis only presented the highest overall cost (809,605.44 USD). CONCLUSION: The two-step algorithm with simultaneous GDH and toxin A/B rapid immunoassay arbitrated by NAAT seems to be the best strategy for CDI diagnosis in developing countries.

Impact of rt-pcr test false-negative results for SARS-CoV-2 surveillance in Mexico

ABSTRACT Background: Underestimation of the number of cases during the coronavirus disease 2019 (COVID-19) pandemic has been a constant concern worldwide. Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA using real-time reverse-transcription polymerase chain reaction (RT-PCR) is the most common method to confirm a case. However, these tests have suboptimal sensitivity. Objective: The objective of the study was to estimate the number of COVID-19 confirmed cases, intensive care unit (ICU) admissions and deaths in Mexico, accounting for the probabilities of false-negative tests. Methods: We used publicly available, national databases of all SARS-CoV-2 tests performed at public laboratories in Mexico between February 27 and October 31, 2020. We used the estimated probabilities of false-negative tests based on the day of clinical sample collection after symptom initiation calculated previously. With the resulting model, we estimated the corrected daily number of cases, ICU admissions, and deaths. Results: Among 2,024,822 people tested in Mexico between February 27 and October 31 with an available result, we estimated 1,248,583 (95% confidence interval 1,094,850-1,572,818) cases, compared to 902,343 cases reported with positive tests. ICU admissions and deaths were 15% and 8% higher than reported, respectively. Conclusion: Accounting for SARS-CoV-2 RT-PCR-based diagnostic testsҠprecision is a simple way to improve estimations for the true number of COVID-19 cases among tested persons.

Advances in Detecting Low Prevalence Somatic TERT Promoter Mutations in Papillary Thyroid Carcinoma.

Background: Two recurrent TERT (telomerase reverse transcriptase) promoter mutations, C228T and C250T, have been reported in thyroid carcinomas and were correlated with high-risk clinicopathological features and a worse prognosis. Although far more frequent in the poorly differentiated and undifferentiated thyroid cancer, the TERT promoter mutations play a significant role on PTC recurrence and disease-specific mortality. However, the prevalence varies considerably through studies and it is uncertain if these differences are due to population variation or the methodology used to detect TERT mutations. In this study we aim to compare three different strategies to detect TERT promoter mutations in PTC. Methods: DNA was isolated from formalin-fixed paraffin-embedded (FFPE) specimens from 89 PTC and 40 paired lymph node metastases. The prevalence of the hot spot TERT C228T and C250T mutations was assessed in FFPE samples using TaqMan SNP genotyping assays. Random samples were tested by Sanger Sequencing and droplet digital PCR (ddPCR). Results: In general, 16 out of 89 (18%) PTC samples and 14 out of 40 (35%) lymph node metastases harbored TERT promoter mutations by TaqMan assay. Sanger sequencing, performed in random selected samples, failed to detect TERT mutations in four samples that were positive by TaqMan SNP genotyping assay. Remarkably, ddPCR assay allowed detection of TERT promoter mutations in six samples that harbor very low mutant allele frequency (≤ 2%) and were negative by both genotype assay and Sanger Sequencing. Conclusion: This study observed a good concordance among the methodologies used to detect TERT promoter mutations when a high percentage of mutated alleles was present. Sanger analysis demonstrated a limit of detection for mutated alleles. Therefore, the prevalence of TERT promoter mutations in PTC may be higher than previously reported, since most studies have conventionally used Sanger sequencing. The efficient characterization of genetic alterations that are used as preoperative or postoperative diagnostic, risk stratification of the patient and individualized treatment decisions, mainly in highly heterogeneous tumors, require highly sensitive and specific approaches.

App-based symptom tracking to optimize SARS-CoV-2 testing strategy using machine learning.

BACKGROUND: Tests are scarce resources, especially in low and middle-income countries, and the optimization of testing programs during a pandemic is critical for the effectiveness of the disease control. Hence, we aim to use the combination of symptoms to build a predictive model as a screening tool to identify people and areas with a higher risk of SARS-CoV-2 infection to be prioritized for testing. MATERIALS AND METHODS: We performed a retrospective analysis of individuals registered in "Dados do Bem," a Brazilian app-based symptom tracker. We applied machine learning techniques and provided a SARS-CoV-2 infection risk map of Rio de Janeiro city. RESULTS: From April 28 to July 16, 2020, 337,435 individuals registered their symptoms through the app. Of these, 49,721 participants were tested for SARS-CoV-2 infection, being 5,888 (11.8%) positive. Among self-reported symptoms, loss of smell (OR[95%CI]: 4.6 [4.4-4.9]), fever (2.6 [2.5-2.8]), and shortness of breath (2.1 [1.6-2.7]) were independently associated with SARS-CoV-2 infection. Our final model obtained a competitive performance, with only 7% of false-negative users predicted as negatives (NPV = 0.93). The model was incorporated by the "Dados do Bem" app aiming to prioritize users for testing. We developed an external validation in the city of Rio de Janeiro. We found that the proportion of positive results increased significantly from 14.9% (before using our model) to 18.1% (after the model). CONCLUSIONS: Our results showed that the combination of symptoms might predict SARS-Cov-2 infection and, therefore, can be used as a tool by decision-makers to refine testing and disease control strategies.

Fast and Robust Identity-by-Descent Inference with the Templated Positional Burrows-Wheeler Transform.

Estimating the genomic location and length of identical-by-descent (IBD) segments among individuals is a crucial step in many genetic analyses. However, the exponential growth in the size of biobank and direct-to-consumer genetic data sets makes accurate IBD inference a significant computational challenge. Here we present the templated positional Burrows-Wheeler transform (TPBWT) to make fast IBD estimates robust to genotype and phasing errors. Using haplotype data simulated over pedigrees with realistic genotyping and phasing errors, we show that the TPBWT outperforms other state-of-the-art IBD inference algorithms in terms of speed and accuracy. For each phase-aware method, we explore the false positive and false negative rates of inferring IBD by segment length and characterize the types of error commonly found. Our results highlight the fragility of most phased IBD inference methods; the accuracy of IBD estimates can be highly sensitive to the quality of haplotype phasing. Additionally, we compare the performance of the TPBWT against a widely used phase-free IBD inference approach that is robust to phasing errors. We introduce both in-sample and out-of-sample TPBWT-based IBD inference algorithms and demonstrate their computational efficiency on massive-scale data sets with millions of samples. Furthermore, we describe the binary file format for TPBWT-compressed haplotypes that results in fast and efficient out-of-sample IBD computes against very large cohort panels. Finally, we demonstrate the utility of the TPBWT in a brief empirical analysis, exploring geographic patterns of haplotype sharing within Mexico. Hierarchical clustering of IBD shared across regions within Mexico reveals geographically structured haplotype sharing and a strong signal of isolation by distance. Our software implementation of the TPBWT is freely available for noncommercial use in the code repository (https://github.com/23andMe/phasedibd, last accessed January 11, 2021).

Clinical and laboratory characteristics of sars-cov-2 infection in children and adolescents / Características clínicas e laboratoriais da infecção por sars-cov-2 em crianças e adolescentes

ABSTRACT Objective: To present the current evidence on clinical and laboratory characteristics of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during childhood and adolescence. Data source: This is a narrative review conducted in the databases: Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Latin American and Caribbean Health Sciences Literature in the Virtual Health Library (LILACS/VHL), Scopus, Web of Science, Cochrane Library, portal of the Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES), Scientific Electronic Library Online (SciELO), ScienceDirect, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). The terms used were SARS-CoV-2, COVID-19, novel coronavirus, child, newborn, and adolescent. Data synthesis: Unlike adults, most children infected by SARS-CoV-2 have mild or asymptomatic clinical presentations. Symptomatic children mainly have low fever and cough, with some associated gastrointestinal symptoms. Severe cases are rare and occur especially in infants under one year of age. Detection of viral particles in feces seems to be more persistent in children and can be used as a tool for diagnosis and control of the quarantine period. Different from adults, children can present distinct inflammatory responses, as has happened in new cases of Kawasaki-like syndrome associated with SARS-CoV-2 infection. Conclusions: Most children have asymptomatic or mild presentations, with a prevalence of fever, cough, and gastrointestinal symptoms. New cases with different systemic inflammatory reactions in children have been reported, with clinical manifestations distinct from those typically found in adults.

RESUMO Objetivo: Apresentar as atuais evidências sobre as características clínicas e laboratoriais da infecção pelo coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2) durante a infância e a adolescência. Fonte de dados: Revisão narrativa realizada nas bases de dados Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Literatura Latino-Americana e do Caribe em Ciências da Saúde na Biblioteca Virtual em Saúde (LILACS/BVS), Scopus, Web of Science, Cochrane Library, portal da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Scientific Electronic Library Online (SciELO), ScienceDirect e Cumulative Index to Nursing and Allied Health Literature (CINAHL), com o uso dos termos SARS-CoV-2, COVID-19 e novo coronavírus e criança, recém-nascido e adolescente. Síntese dos dados: Diferentemente dos adultos, as crianças infectadas pelo SARS-CoV-2 apresentam formas clínicas leves ou assintomáticas na maior parte dos casos. As crianças sintomáticas apresentam predominantemente febre baixa e tosse, com alguns sintomas gastrointestinais associados. Casos graves são a minoria e ocorrem especialmente abaixo de um ano de idade. A detecção de partículas virais em fezes parece ser mais persistente em crianças, podendo servir como ferramenta diagnóstica e de controle do tempo de quarentena. Diferentemente dos adultos, as crianças podem apresentar respostas inflamatórias distintas, como tem ocorrido nos novos casos de síndrome de Kawasaki-like associada à infecção pelo SARS-CoV-2. Conclusões: Crianças, na sua maioria, apresentam quadros assintomáticos ou leves, com predomínio de febre, tosse e sintomas gastrointestinais. Novos relatos de diferentes reações sistêmicas inflamatórias em crianças têm sido notados, com manifestações clínicas distintas daquelas tipicamente observadas em adultos.

CLINICAL AND LABORATORY CHARACTERISTICS OF SARS-COV-2 INFECTION IN CHILDREN AND ADOLESCENTS.

OBJECTIVE: To present the current evidence on clinical and laboratory characteristics of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during childhood and adolescence. DATA SOURCE: This is a narrative review conducted in the databases: Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Latin American and Caribbean Health Sciences Literature in the Virtual Health Library (LILACS/VHL), Scopus, Web of Science, Cochrane Library, portal of the Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES), Scientific Electronic Library Online (SciELO), ScienceDirect, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). The terms used were SARS-CoV-2, COVID-19, novel coronavirus, child, newborn, and adolescent. DATA SYNTHESIS: Unlike adults, most children infected by SARS-CoV-2 have mild or asymptomatic clinical presentations. Symptomatic children mainly have low fever and cough, with some associated gastrointestinal symptoms. Severe cases are rare and occur especially in infants under one year of age. Detection of viral particles in feces seems to be more persistent in children and can be used as a tool for diagnosis and control of the quarantine period. Different from adults, children can present distinct inflammatory responses, as has happened in new cases of Kawasaki-like syndrome associated with SARS-CoV-2 infection. CONCLUSIONS: Most children have asymptomatic or mild presentations, with a prevalence of fever, cough, and gastrointestinal symptoms. New cases with different systemic inflammatory reactions in children have been reported, with clinical manifestations distinct from those typically found in adults.

Cervical Stenosis: Previously Unrecognized Cause of False-Negative Human Papillomavirus Tests in Women Developing Cervical Cancer.

OBJECTIVES: Cervical stenosis can jeopardize adequate posttreatment cytologic follow-up of patients treated for high-grade cervical intraepithelial lesions. An impact on human papillomavirus (HPV) testing has not been described. MATERIALS AND METHODS: We describe 2 patients with cervical stenosis, followed by cytology and HPV co-testing after excisions of high-grade cervical intraepithelial lesions. Each had 1 or more co-test "double-negative" results. Hysterectomies revealed unexpected cervical carcinomas. RESULTS: In case 1, an 80-year-old woman with complete cervical stenosis and earlier high-grade squamous dysplasia presented with abdominal pain, nausea, and an enlarged uterus. Attempted endometrial biopsy was unsuccessful. Cytology and HPV tests 9 months earlier were negative. Hysterectomy revealed a cervical squamous carcinoma. In case 2, a 40-year-old woman followed conservatively after excision of endocervical adenocarcinoma in situ had 5 follow-up cytology and HPV co-tests. All were HPV negative. Elective hysterectomy revealed cervical adenocarcinoma. Both carcinomas tested HPV positive. CONCLUSIONS: Cervical stenosis in women developing cervical cancer can cause misleading sampling and false-negative HPV test results.

Métodos diagnósticos para la infección por SARS-CoV-2 / Diagnostic methods for SARS-CoV-2 infection

En diciembre de 2019 se identificó el virus SARS-CoV-2, cuya rápida propagación global puso en estado de emergencia al mundo entero, llevando al ser humano a una situación sin antecedente cercano. El objetivo de esta revisión es describir los métodos diagnósticos utilizados actualmente para identificar la infección por SARS-CoV-2. Las manifestaciones clínicas y el espectro imagenológico de la enfermedad son muy inespecíficos y no permiten realizar un diagnóstico certero. Por esta razón, es esencial una apropiada toma de muestra respiratoria en el momento y sitio anatómico adecuado para un diagnóstico preciso de COVID-19. La técnica de muestreo más utilizada es el hisopado nasofaríngeo y la prueba diagnóstica más fiable se basa en la retrotranscripción seguida por reacción en cadena de la polimerasa en tiempo real (RT-PCR). No obstante, existen otras técnicas moleculares, como también tests serológicos para detectar anticuerpos o fragmentos antigénicos del SARS-CoV-2. Más allá de la precisión diagnóstica, es importante tener en cuenta la probabilidad basal (pretest) para interpretar correctamente el resultado obtenido y aislar aquellos posibles falsos negativos. Con el objetivo de evitar la saturación del sistema de salud es imprescindible contar con información y métodos diagnósticos precisos para detectar tempranamente los focos de infección y reducir la transmisión comunitaria, utilizando eficazmente los diferentes recursos diagnósticos. (AU)

In December 2019, the SARS-CoV-2 virus was identified for the first time, whose rapid global spread put the entire world in a state of emergency, leading humans to an unprecedented situation with no immediate history. The main purpose of this review is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. The clinical manifestations and the imaging spectrum of the disease are nonspecific and do not allow an accurate diagnosis to be made. For this reason, an appropriate respiratory sampling at the right time and anatomical site is essential for an accurate diagnosis of COVID-19. The most widely used sampling technique is nasopharyngeal swab, and the most reliable diagnostic test is by reverse transcription followed by real-time polymerase chain reaction (RT-PCR). However, there are other molecular techniques, as well as serological tests to detect antibodies or antigenic fragments of SARS-CoV-2. Beyond the diagnostic precision, it is important to take into account the baseline probability (pre-test) to correctly interpret the result obtained and isolate those possible false negatives. In order to avoid saturation of the health system, it is essential to have accurate information and diagnostic methods to detect outbreaks of infection in early stages and to reduce communitary transmission, making effective use of the various diagnostic resources. Coronavirus infections/diagnosis, viral/diagnosis, pandemics, clinical laboratory techniques, real-time polymerase chain reaction, antigens, viral/analysis. (AU)

Detection of SARS-CoV-2 in nasal swabs using MALDI-MS.

Detection of SARS-CoV-2 using RT-PCR and other advanced methods can achieve high accuracy. However, their application is limited in countries that lack sufficient resources to handle large-scale testing during the COVID-19 pandemic. Here, we describe a method to detect SARS-CoV-2 in nasal swabs using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and machine learning analysis. This approach uses equipment and expertise commonly found in clinical laboratories in developing countries. We obtained mass spectra from a total of 362 samples (211 SARS-CoV-2-positive and 151 negative by RT-PCR) without prior sample preparation from three different laboratories. We tested two feature selection methods and six machine learning approaches to identify the top performing analysis approaches and determine the accuracy of SARS-CoV-2 detection. The support vector machine model provided the highest accuracy (93.9%), with 7% false positives and 5% false negatives. Our results suggest that MALDI-MS and machine learning analysis can be used to reliably detect SARS-CoV-2 in nasal swab samples.