scholarly journals Study of Various Diagnostic Tests for COVID-19: A Review

2021 ◽  
Vol 1 (1) ◽  
pp. 153-162
Author(s):  
Manika Bhatia ◽  
Aditri ◽  
Shrreya Siingh ◽  
Yashaswy ◽  
Himanshu ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Early Diagnosis ◽  
Diagnostic Tests ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Serological Testing ◽  
Diagnostic Kits ◽  
Exponential Increase ◽  
Entire World

The coronavirus disease of 2019 (COVID-19), a nightmare of this century, has become an ongoing global health emergency for the entire world. This dreadful disease is believed to have originated from China and has now spread worldwide. To date, more than 170 million people have been found affected by this virus, namely “severe acute respiratory syndrome coronavirus-2” (SARS-CoV-2). With the exponential increase in the patients affected by the SARS-CoV-2, the need for testing has also increased tremendously. Early diagnosis is essential to prevent the extensive spread of the disease because of the faster rate of infection. In this regard, various diagnostic techniques are employed for the detection of the infection in symptomatic and asymptomatic COVID-19 individuals. To provide diagnostic care for the control of the disease, various tests like serological testing, nucleic acid amplification test (NAAT), rapid antigen-based testing, and paper-based testing have been developed and are presently in good use. The present mini-review is an attempt to outline the currently available diagnostic kits for the detection of the SARS-CoV-2 causing COVID-19.

scholarly journals A Retrospective Cross-Sectional Study of the Utility of Cartridge-Based Nucleic Acid Amplification Test in Diagnosis of Pulmonary and Extrapulmonary Tuberculosis in People Living with HIV in Second Highest HIV Prevalent State in India

2021 ◽  
Author(s):  
Tade Bagbi ◽  
Ningthoukhongjam Reema ◽  
S. Bhagyabati Devi ◽  
Thangjam Gautam Singh ◽  
Mohammad Jaleel ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Cross Sectional Study ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Rifampicin Resistance ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Sectional Study ◽  
Cross Sectional ◽  
Smear Negative

Abstract Introduction Tuberculosis (TB) in people living with human immunodeficiency virus (PLHIV) is difficult to diagnose due to fewer organisms in sputum and extrapulmonary samples. Sputum culture takes 4 to 8 weeks for growth of the mycobacteria. Delayed treatment for TB in PLHIV leads to increased mortality. This study evaluated cartridge-based nucleic acid amplification test (CBNAAT) as a diagnostic tool for diagnosis of pulmonary TB (PTB) and extrapulmonary TB (EPTB) in PLHIV in the second most HIV prevalent state in India and for comparing its efficacy between Ziehl–Neelsen (ZN) staining sputum smear–positive and sputum smear–negative TB. Methods This cross-sectional study was conducted in RIMS, Imphal, with 167 PLHIV patients, age 15 years or older, having signs and symptoms of TB. Appropriate samples for sputum microscopy and CBNAAT were sent. Conclusion The overall sensitivity of sputum smear for acid-fast bacillus (AFB) was found to be 30.71% and that of CBNAAT was 38.57%. Sensitivity of CBNAAT for sputum smear–positive and sputum smear–negative TB was 100 and 11.3%, respectively. Sensitivity of ZN smear for AFB of EPTB sample was 48.1% and that of CBNAAT was 59.25%. In both PTB and EPTB, CBNAAT showed an increase in diagnosis of microbiologically confirmed PTB cases by 7.8 and 11.1%, respectively, over and above the cases diagnosed by ZN smear microscopy. Rifampicin resistance was detected in five patients. We conclude that CBNAAT is a rapid test with better sensitivity in diagnosis of PTB and EPTB in PLHIV, compared with ZN smear microscopy. It detects rifampicin resistance for multidrug-resistant TB and helps in early treatment intervention.

scholarly journals Nucleic Acid Amplification Test Quantitation as Predictor of Toxin Presence in Clostridium difficile Infection

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
M. J. T. Crobach ◽  
N. Duszenko ◽  
E. M. Terveer ◽  
C. M. Verduin ◽  
E. J. Kuijper
Keyword(s):  
Nucleic Acid ◽  
Clostridium Difficile ◽  
Characteristic Curve ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Toxin A ◽  
Toxin B ◽  
Content Type ◽  
Quantitative Results ◽  
Testing Algorithm

ABSTRACT Multistep algorithmic testing in which a sensitive nucleic acid amplification test (NAAT) is followed by a specific toxin A and toxin B enzyme immunoassay (EIA) is among the most accurate methods for Clostridium difficile infection (CDI) diagnosis. The obvious shortcoming of this approach is that multiple tests must be performed to establish a CDI diagnosis, which may delay treatment. Therefore, we sought to determine whether a preliminary diagnosis could be made on the basis of the quantitative results of the first test in algorithmic testing, which provide a measure of organism burden. To do so, we retrospectively analyzed two large collections of samples ( n = 2,669 and n = 1,718) that were submitted to the laboratories of two Dutch hospitals for CDI testing. Both hospitals apply a two-step testing algorithm in which a NAAT is followed by a toxin A/B EIA. Of all samples, 208 and 113 samples, respectively, tested positive by NAAT. Among these NAAT-positive samples, significantly lower mean quantification cycle ( C q ) values were found for patients whose stool eventually tested positive for toxin, compared with patients who tested negative for toxin (mean C q values of 24.4 versus 30.4 and 26.8 versus 32.2; P < 0.001 for both cohorts). Receiver operating characteristic curve analysis was performed to investigate the ability of C q values to predict toxin status and yielded areas under the curve of 0.826 and 0.854. Using the optimal C q cutoff values, prediction of the eventual toxin A/B EIA results was accurate for 78.9% and 80.5% of samples, respectively. In conclusion, C q values can serve as predictors of toxin status but, due to the suboptimal correlation between the two tests, additional toxin testing is still needed.

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