Increased Detection of Mycobacterium tuberculosis Disease Using a Tissue-Based Laboratory-Developed Polymerase Chain Reaction Assay Compared to Standard Diagnostics

2021 ◽  
Author(s):  
Natalie A. Mackow ◽  
Rita Abi-Raad ◽  
Christopher A. Keratanzas ◽  
Pei Hui ◽  
Maricar Malinis ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Mycobacterium Tuberculosis ◽  
Clinical Performance ◽  
Chain Reaction ◽  
Clinical Sensitivity ◽  
Variable Sensitivity ◽  
Polymerase Chain ◽  
Mean Time ◽  
Tuberculosis Disease ◽  
Composite Reference Standard

Standard diagnostics for Mycobacterium tuberculosis (MTB) including acid-fast bacilli (AFB) smear and culture, and Xpert™ MTB/RIF real-time Polymerase Chain Reaction (RT-PCR; Xpert) have variable sensitivity and/or long turnaround times. We describe the clinical performance of a laboratory-developed tissue-based MTB PCR compared with AFB culture and Xpert using a composite reference standard (CRS). Over an 8-year period, MTB PCR was performed on pulmonary, pleural, or lymph node specimens for 36 patients. Of these, 11 met criteria for confirmed/probable MTB using CRS. MTB PCR was positive in 100% (11/11), AFB cultures were positive in 73% (8/11), and Xpert in 0% (0/4). MTB PCR was negative in 25 cases of “No MTB” (100% specific). The MTB PCR assay resulted faster than positive AFB culture (mean time 4.3 versus 21.2 days). Tissue-based MTB PCR was associated with increased and rapid detection of MTB, improving clinical sensitivity in strongly suspected MTB cases.

scholarly journals EXPRESS: Clinical performance of the Elecsys® Anti-SARS-CoV-2 combined in an algorithm with two specific anti-IgG immunoassays for the evaluation of the serological response of patients with COVID-19 in a population with a high prevalence of infection

2021 ◽  
pp. 000456322110380
Author(s):  
Xavier Gabaldó-Barrios ◽  
Simona Iftimie ◽  
Anna Hernández-Aguilera ◽  
Isabel Pujol ◽  
Frederic Ballester ◽  
...  
Keyword(s):  
Immune Response ◽  
Polymerase Chain Reaction ◽  
Predictive Value ◽  
Clinical Performance ◽  
Polymerase Chain Reaction Test ◽  
Serological Response ◽  
Chain Reaction ◽  
Automated Assay ◽  
High Prevalence ◽  
Polymerase Chain

Background: Anti-SARS-CoV-2 antibodies have been used in the study of the immune response in infected patients. However, differences in sensitivity and specificity have been reported, depending on the method of analysis. The aim of the present study was to evaluate the diagnostic accuracy of an algorithm in which a high-throughput automated assay for total antibodies was used for screening and two semi-automated IgG-specific methods were used to confirm the results, and also to correlate the analytical results with the clinical data and the time elapsed since infection. Methods: We studied 306 patients, some hospitalized and some outpatients, belonging to a population with a high prevalence of COVID-19. One-hundred and ten patients were classified as SARS-CoV-2 negative and 196 as positive by polymerase chain reaction. Results: The algorithm and automated assay alone had a specificity and a positive predictive value of 100%, although the sensitivity and negative predictive value of the algorithm was higher. Both methods showed a good sensitivity from day 11 of the onset of symptoms in asymptomatic and symptomatic patients. The absorbance of the total antibodies was significantly higher in severely symptomatic than in asymptomatic or mildly symptomatic patients, which suggests the antibody level was higher. We found 15 patients that did not present seroconversion at 12 days from the onset of symptoms or the first polymerase chain reaction test. Conclusion: This study highlights the proper functioning of algorithms in the diagnosis of the immune response to COVID-19, which can help to define testing strategies against this disease.

scholarly journals Deteção de Mycobacterium tuberculosis em amostras clínicas por reação em cadeia da polimerase utilizando primers baseados na região intergênica plcB-plcC

2007 ◽  
Vol 33 (4) ◽  
pp. 437-442
Author(s):  
Hermides Pinto Júnior ◽  
Claudia Giuliano Bica ◽  
Moisés Palaci ◽  
Reynaldo Dietze ◽  
Luiz Augusto Basso ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Mycobacterium Tuberculosis ◽  
Phospholipase C ◽  
Chain Reaction ◽  
Polymerase Chain

OBJETIVO: Desenvolver um sistema para o diagnóstico molecular da tuberculose por reação em cadeia da polimerase, do inglês polymerase chain reaction (PCR), pela construção de primers baseados na diferença da organização de uma região intergênica da fosfolipase (phospholipase) C (região plcB-plcC), que diferencia Mycobacterium tuberculosis das outras micobactérias. MÉTODOS: Um produto de PCR com o tamanho esperado (432 pb) foi obtido somente de M. tuberculosis e M. africanum. Um total de 33 isolados micobacterianos e 273 amostras clínicas de pacientes com suspeita de tuberculose foram examinados. Estes foram submetidos ao estudo comparativo da técnica de PCR contra o cultivo. RESULTADOS: Os dados mostraram 93,8% de exatidão para PCR contra o cultivo (p < 0,0001), 93,1% de sensibilidade (IC: 88,7-96,0) e especificidade de 96,4% (IC: 96,1-99,4). O valor de Kappa foi de 0,82, demonstrando um alinhamento perfeito para a verificação do grau de concordância entre os testes. CONCLUSÃO: O uso da região plcB-plcC para a amplificação por PCR é mostrado como uma ferramenta importante e de confiança para o diagnóstico específico de tuberculose nas amostras clínicas analisadas.

scholarly journals Performance of an in-house real-time polymerase chain reaction for identification of Mycobacterium tuberculosis isolates in laboratory routine diagnosis from a high burden setting

2016 ◽  
Vol 111 (9) ◽  
pp. 545-550 ◽  
Author(s):  
Juliana Failde Gallo ◽  
Juliana Maira Watanabe Pinhata ◽  
Erica Chimara ◽  
Maria Gisele Gonçalves ◽  
Lucila Okuyama Fukasawa ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Mycobacterium Tuberculosis ◽  
Real Time ◽  
Chain Reaction ◽  
High Burden ◽  
Routine Diagnosis ◽  
Polymerase Chain
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