scholarly journals Impact of COVID-19 pre-test probability on positive predictive value of high cycle threshold SARS-CoV-2 real-time reverse transcription PCR test results

2021 ◽  
Author(s):  
Jonathan B. Gubbay ◽  
Heather Rilkoff ◽  
Heather L. Kristjanson ◽  
Jessica D. Forbes ◽  
Michelle Murti ◽  
...  
Keyword(s):  
Real Time ◽  
Reverse Transcription ◽  
False Positive ◽  
Rdrp Gene ◽  
Positive Test ◽  
Test Results ◽  
Rt Pcr ◽  
Pcr Assay ◽  
False Positive Test ◽  
Test Probability

ABSTRACTBackgroundPerformance characteristics of SARS-CoV-2 nucleic acid detection assays are understudied within contexts of low pre-test probability, including screening asymptomatic persons without epidemiological links to confirmed cases, or asymptomatic surveillance testing. SARS-CoV-2 detection without symptoms may represent resolved infection with persistent RNA shedding, presymptomatic or asymptomatic infection, or a false positive test. This study assessed clinical specificity of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) assays by retesting positive specimens from five pre-test probability groups ranging from high to low with an alternate assay.Materials and MethodsA total of 122 rRT-PCR positive specimens collected from unique patients between March and July 2020 were retested using a laboratory-developed nested RT-PCR assay targeting the RNA-dependent RNA polymerase (RdRp) gene followed by Sanger sequencing.ResultsSignificantly less positive results in the lowest pre-test probability group (facilities with institution-wide screening having ≤ 3 positive asymptomatic cases) were reproduced with the nested RdRp gene RT-PCR assay than in all other groups combined (5/32, 15·6% vs 61/90, 68%; p <0·0001), and in each subgroup with higher pre-test probability (individual subgroup range 50·0% to 85·0%).ConclusionsA higher proportion of false-positive test results are likely with lower pre-test probability. Positive SARS-CoV-2 PCR results should be interpreted within the context of patient history, clinical setting, known exposure, and estimated community disease prevalence. Large-scale SARS-CoV-2 screening testing initiatives among low pre-test probability populations should be evaluated thoroughly prior to implementation given the risk of false positives and consequent potential for harm at the individual and population level.

scholarly journals Impact of COVID-19 pre-test probability on positive predictive value of high cycle threshold SARS-CoV-2 real-time reverse transcription PCR test results

2021 ◽  
pp. 1-18
Author(s):  
Jonathan B. Gubbay ◽  
Heather Rilkoff ◽  
Heather L. Kristjanson ◽  
Jessica D. Forbes ◽  
Michelle Murti ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Real Time ◽  
Reverse Transcription ◽  
Predictive Value ◽  
Large Scale ◽  
Rdrp Gene ◽  
Nucleic Acid Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Test Probability

Abstract Objectives Performance characteristics of SARS-CoV-2 nucleic acid detection assays are understudied within contexts of low pre-test probability, including screening asymptomatic persons without epidemiological links to confirmed cases, or asymptomatic surveillance testing. SARS-CoV-2 detection without symptoms may represent presymptomatic or asymptomatic infection, resolved infection with persistent RNA shedding, or a false positive test. This study assessed positive predictive value of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) assays by retesting positive specimens from five pre-test probability groups ranging from high to low with an alternate assay. Methods A total of 122 rRT-PCR positive specimens collected from unique patients between March and July 2020 were retested using a laboratory-developed nested RT-PCR assay targeting the RNA-dependent RNA polymerase (RdRp) gene followed by Sanger sequencing. Results Significantly fewer (15.6%) positive results in the lowest pre-test probability group (facilities with institution-wide screening having ≤ 3 positive asymptomatic cases) were reproduced with the nested RdRp gene RT-PCR assay than in each of the four groups with higher pre-test probability (individual group range 50·0% to 85·0%). Conclusions Large-scale SARS-CoV-2 screening testing initiatives among low pre-test probability populations should be evaluated thoroughly prior to implementation given the risk of false positives and consequent potential for harm at the individual and population level.

scholarly journals Estimating the false-negative test probability of SARS-CoV-2 by RT-PCR

2020 ◽  
Vol 25 (50) ◽  
Author(s):  
Paul S Wikramaratna ◽  
Robert S Paton ◽  
Mahan Ghafari ◽  
José Lourenço
Keyword(s):  
Symptom Onset ◽  
False Positive ◽  
False Negative ◽  
Positive Test ◽  
Rt Pcr ◽  
Negative Test ◽  
False Positive Test ◽  
True Number ◽  
Test Probability ◽  
False Negative Test

Background Reverse-transcription PCR (RT-PCR) assays are used to test for infection with the SARS-CoV-2 virus. RT-PCR tests are highly specific and the probability of false positives is low, but false negatives are possible depending on swab type and time since symptom onset. Aim To determine how the probability of obtaining a false-negative test in infected patients is affected by time since symptom onset and swab type. Methods We used generalised additive mixed models to analyse publicly available data from patients who received multiple RT-PCR tests and were identified as SARS-CoV-2 positive at least once. Results The probability of a positive test decreased with time since symptom onset, with oropharyngeal (OP) samples less likely to yield a positive result than nasopharyngeal (NP) samples. The probability of incorrectly identifying an uninfected individual due to a false-negative test was considerably reduced if negative tests were repeated 24 hours later. For a small false-positive test probability (<0.5%), the true number of infected individuals was larger than the number of positive tests. For a higher false-positive test probability, the true number of infected individuals was smaller than the number of positive tests. Conclusion NP samples are more sensitive than OP samples. The later an infected individual is tested after symptom onset, the less likely they are to test positive. This has implications for identifying infected patients, contact tracing and discharging convalescing patients who are potentially still infectious.

Effects of organic acids and common household products on the occurrence of false positive test results using immunochromatographic assays

2020 ◽  
Vol 308 ◽  
pp. 110165
Author(s):  
Megan M. Foley ◽  
Catherine O. Brown ◽  
Christian G. Westring ◽  
Phillip B. Danielson ◽  
Heather E. McKiernan
Keyword(s):  
Organic Acids ◽  
False Positive ◽  
Positive Test ◽  
Test Results ◽  
False Positive Test ◽  
Household Products

Increased detection of rotavirus using a real time reverse transcription-polymerase chain reaction (RT-PCR) assay in stool specimens from children with diarrhea

2004 ◽  
Vol 72 (3) ◽  
pp. 496-501 ◽  
Author(s):  
Xiaoli L. Pang ◽  
Bonita Lee ◽  
Nasim Boroumand ◽  
Barbara Leblanc ◽  
Jutta K. Preiksaitis ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Reverse Transcription ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Stool Specimens ◽  
Polymerase Chain

False-Positive Test Results in a Patient With Severe Hepatitis

2015 ◽  
Vol 175 (2) ◽  
pp. 161
Author(s):  
Simina R. Luca ◽  
Mandana Kayedi ◽  
Brian M. Wong
Keyword(s):  
False Positive ◽  
Positive Test ◽  
Test Results ◽  
Severe Hepatitis ◽  
False Positive Test

H1N1 vaccination and false-positive test results for hepatitis B core antibody in health workers

Transfusion ◽  
2011 ◽  
Vol 51 (7) ◽  
pp. 1595-1596
Author(s):  
Patrícia R. Araújo ◽  
Guilherme A. Albertoni ◽  
Silvia R. Rizzo ◽  
Fabrício O. Carvalho ◽  
José A. Barreto
Keyword(s):  
Hepatitis B ◽  
False Positive ◽  
Health Workers ◽  
Positive Test ◽  
Test Results ◽  
False Positive Test
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