scholarly journals Low Cycle Threshold Value in Xpert MTB/RIF Assay May Herald False Detection of Tuberculosis and Rifampicin Resistance: A Study of Two Cases

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Jean Claude S Ngabonziza ◽  
Tom Decroo ◽  
Rodrigue Maniliho ◽  
Yves M Habimana ◽  
Armand Van Deun ◽  
...  
Keyword(s):  
Threshold Value ◽  
Rifampicin Resistance ◽  
False Detection ◽  
Cycle Threshold ◽  
Resistant Tuberculosis

Abstract We report 2 cases for whom Xpert MTB/RIF falsely signaled rifampicin-resistant tuberculosis, based on unusually low cycle threshold and 3 of 5 probes missing. Other mycobacterial tests were negative. Further optimization of the Xpert MTB/RIF algorithm is warranted.

scholarly journals Association of Cartridge Based Nucleic Acid Amplification Test (CBNAAT) Grading on the Basis of Cycle Threshold Value with Conventional Microbiological Diagnosis in Pediatric Tuberculosis

2021 ◽  
Vol 7 (2) ◽  
pp. 72-77
Author(s):  
Bineeta Kashyap ◽  
Neha Gupta ◽  
Pooja Dewan ◽  
NP Singh ◽  
Ashwani Khanna
Keyword(s):  
Nucleic Acid ◽  
Positive Association ◽  
Threshold Value ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Microbiological Diagnosis ◽  
Significant Positive Association ◽  
Cycle Threshold ◽  
Culture Positivity ◽  
Pediatric Tuberculosis

Background: Microbiological confirmation of tuberculosis disease in children remains difficult due to paucibacillary disease and inability to obtain optimal samples. Recently introduced Cartridge based nucleic acid amplification test (CBNAAT) has improved microbiological diagnosis in pediatric tuberculosis. Objectives: We aimed to study association of CBNAAT grading based on cycle threshold value with conventional microbiological diagnosis. Methodology: This prospective study was conducted over a period from November 2016 to October 2017 in the Departments of Microbiology and Pediatrics, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi. CBNAAT positive pediatric TB cases ≤12 years were recruited and subjected to Ziehl-Neelsen staining for acid fast bacilli (AFB) & culture on Lowenstein Jensen medium. CBNAAT positivity was graded based on cycle threshold value: very low, low, medium and high. Results: Smear and culture positivity was highest (100%) among specimens with high positive CBNAAT result based on CT value. Time to culture positivity was inversely related to CBNAAT grading (p=0.000). Conclusion: CBNAAT grading has significant positive association with smear and culture positivity. Bangladesh Journal of Infectious Diseases 2020;7(2):72-77

scholarly journals A Real-World Comparison of SARS-CoV-2 Rapid Antigen vs. Polymerase Chain Reaction Testing in Florida

2021 ◽  
Author(s):  
Lao-Tzu Allan-Blitz ◽  
Jeffrey D. Klausner
Keyword(s):  
Polymerase Chain Reaction ◽  
Real World ◽  
Threshold Value ◽  
Test Results ◽  
Chain Reaction ◽  
Cycle Threshold ◽  
Large Populations ◽  
Symptom Status ◽  
Polymerase Chain ◽  
Antigen Tests

Background The reported sensitivity of rapid, antigen-based diagnostics for SARS-CoV-2 infection varies. Few studies have evaluated rapid antigen tests in real-world settings or among large populations. Methods Beginning October 2020, Florida offered individuals presenting for SARS-CoV-2 testing polymerase chain reaction (PCR) testing if they tested positive by the Abbott BinaxNOW TM COVID-19 Ag Card, were symptomatic, or required or requested PCR testing. We compared test results among individuals who received both types of tests at four publicly-accessible testing sites across Florida. We calculated the positive percent agreement (PPA) between the two test types by symptom status. Subsequently, we evaluated the PPA among individuals regardless of symptoms with lower cycle threshold values (<30). Results Overall, 18,457 individuals were tested via both methods, of which 3,153 (17.1%) were positive by PCR. The PPA for the Abbott BinaxNOW TM COVID-19 Ag Card using the PCR comparator was 49.2% (95% CI 47.4%-50.9%). That performance was moderately improved among symptomatic individuals (51.9%; 95% CI 49.7%-54.0%). When restricted to positive PCR tests with a cycle threshold value <30, regardless of symptom status, the PPA was 75.3% (95% CI 72.8%-77.6%). Conclusion The PPA of the Abbott BinaxNOW TM COVID-19 Ag Card with PCR was lower than among previous reports. Our findings may reflect the performance of the BinaxNOW TM antigen test in real-world settings.

scholarly journals A routine blood test-associated predictive model and application for tuberculosis diagnosis: a retrospective cohort study from northwest China

2019 ◽  
Vol 47 (7) ◽  
pp. 2993-3007 ◽  
Author(s):  
Kui Li ◽  
Sheng-Xi Liu ◽  
Cai-Yong Yang ◽  
Zi-Cheng Jiang ◽  
Jun Liu ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
High Sensitivity ◽  
Threshold Value ◽  
Northwest China ◽  
Optimal Threshold ◽  
Accuracy Rate ◽  
Distribution Width ◽  
Routine Blood ◽  
Resistant Tuberculosis ◽  
Diagnostic Values

Objectives This study aimed to use the results of routine blood tests and relevant parameters to construct models for the prediction of active tuberculosis (ATB) and drug-resistant tuberculosis (DRTB) and to assess the diagnostic values of these models. Methods We performed logistic regression analysis to generate models of plateletcrit-albumin scoring (PAS) and platelet distribution width-treatment-sputum scoring (PTS). Area under the curve (AUC) analysis was used to analyze the diagnostic values of these curves. Finally, we performed model validation and application assessment. Results In the training cohort, for the PAS model, the AUC for diagnosing ATB was 0.902, sensitivity was 82.75%, specificity was 82.20%, accuracy rate was 81.00%, and optimal threshold value was 0.199. For the PTS model, the AUC for diagnosing DRTB was 0.700, sensitivity was 63.64%, specificity was 73.53%, accuracy rate was 89.00%, and optimal threshold value was −2.202. These two models showed significant differences in the AUC analysis, compared with single-factor models. Results in the validation cohort were similar. Conclusions The PAS model had high sensitivity and specificity for the diagnosis of ATB, and the PTS model had strong predictive potential for the diagnosis of DRTB.

scholarly journals Trends in Mycobacterium Tuberculosis and prevalence of Rifampicin Resistance in Eastern zone, Tigray Region, Northern Ethiopia

2020 ◽  
Author(s):  
Getachew Abay Kahsu ◽  
Bahlibi Hailay
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Data Extraction ◽  
Multidrug Resistant ◽  
Cross Sectional Study ◽  
Rifampicin Resistance ◽  
Northern Ethiopia ◽  
Drug Resistant ◽  
Cross Sectional ◽  
Resistant Tuberculosis ◽  
Eastern Zone

Abstract Background Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. The emergence of Mono or multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis (XDR-TB), poses a considerable challenge to Mycobacterium tuberculosis control programs in the worldwide; however, there has been no reliable and organized data on trends and prevalence drug resistance of Mycobacterium tuberculosis in study area; Therefore, aim of this study to determine the trends of Mycobacterium tuberculosis and prevalence of Rifampicin resistance in eastern zone, Tigray, Northern Ethiopia. Methods Hospital based retrospective cross-sectional study was conducted at Adigrat General Hospital from June 01 to August 30, 2019.Data was collected retrospectively from the registration books using data extraction format commence January 01, 2015, December 30, 2018. Data was entered into Epi-Info 3.1 and exported and analyzed using SPSS Version 20. The results were summarized using descriptive statistics, tables, and figures. P values < 0.05 would be considered statistically significant. Result A total of 5,944 Mycobacterium tuberculosis presumptive patients were included in the study. The majority of the study participants were male (58.1%). The median age of the participants was 40.0 (IQR 57, 26) years, the majority age-group was 30-44 years. The overall prevalence of Mycobacterium tuberculosis was 1446 (24.3%). Of the total confirmed cases, 132 (9.1%) were resistant to rifampicin. From total Rifampicin resistant 129 (97.7%) new cases and the rest were previously treated tuberculosis patients. Age, reason for diagnosis, site of presumptive tuberculosis, being HIV infected was found a significant association with our dependent variable; however, only Age and being HIV infected associated with rifampicin resistance. Conclusion In our study, the overall trends of Mycobacterium tuberculosis and prevalence of rifampicin resistance were found high and increased; therefore, maximizing early detection of drug-resistant Mycobacterium tuberculosis and strengthening TB infection control activities and proper implementation of directly observed treatment are recommended reducing the burden of this contagious disease.

A CYCLE THRESHOLD VALUE-BASED EPIDEMIC PROGNOSTICATION TO MONITOR LONG-TERM EPIDEMIOLOGIC TRENDS OF SARS-COV-2 VIRUS

2021 ◽  
pp. 24-30
Author(s):  
Aditi Munmun Sengupta ◽  
Diptendu Chatterjee ◽  
Bibhuti Saha
Keyword(s):  
Meta Analysis ◽  
Threshold Value ◽  
High Viral Load ◽  
World Health ◽  
Rt Pcr ◽  
Cycle Threshold ◽  
Ct Value ◽  
Health Organization ◽  
The Impact

The real-time reverse transcription-polymerase chain reaction (RT-PCR) is considered as the sensitive proof for detecting the viral infection of the SARS-CoV-2 virus obtained from respiratory samples. The quantitative values for the analysis are benecial for estimating the transmissibility of people who test positive for SARS-CoV-2. This can be further achieved by analyzing the samples by semiquantitative means through the interpretation of the cycle threshold (Ct) values of RT-PCR that represent the rst cycle of PCR at which a detectable signal appears during the assays. The Ct value shows a correlation between high viral load and disease infectiousness, which is observed with other respiratory viruses, including the inuenza B infection and rhinovirus infection. Hence, the present study aims to analyze the surveillance of COVID-19 to monitor longer-term epidemiologic trends and trends in deaths due to COVID-19. In order to achieve this aim, the present review was reported to the preferred reporting items for systematic reviews and meta-analysis statements (PRISMA) for analyzing the Ct value-based epidemic predictions and to monitor long-term epidemiologic trends of SARS-CoV-2 virus. Total 33 studies have been nalized for nding out the results of the study. The epidemiologic parameter and a representative of the surveillance data for reporting to the World Health Organization were fullled by analyzing the systematic review and metaanalysis of the selected study. Moreover, the evaluation of the impact of the pandemic on the health care system and society was achieved by analyzing the studies mentioned here.

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