scholarly journals False positives in reverse transcription PCR testing for SARS-CoV-2

2020 ◽  
Author(s):  
Andrew N. Cohen ◽  
Bruce Kessel
Keyword(s):  
False Positive ◽  
Rna Viruses ◽  
False Positives ◽  
Test Results ◽  
Rt Pcr ◽  
External Quality ◽  
Population Prevalence ◽  
Pcr Assays ◽  
Quality Assessments ◽  
Potential Frequency

AbstractBackgroundLarge-scale testing for SARS-CoV-2 by RT-PCR is a key element of the response to COVID-19, but little attention has been paid to the potential frequency and impacts of false positives.MethodsFrom a meta-analysis of external quality assessments of RT-PCR assays of RNA viruses, we derived a conservative estimate of the range of false positive rates that can reasonably be expected in SARS-CoV-2 testing, and analyzed the effect of such rates on analyses of regional test data and estimates of population prevalence and asymptomatic ratio.FindingsReview of external quality assessments revealed false positive rates of 0-16.7%, with an interquartile range of 0.8-4.0%. Such rates would have large impacts on test data when prevalence is low. Inclusion of such rates significantly alters four published analyses of population prevalence and asymptomatic ratio.InterpretationThe high false discovery rate that results, when prevalence is low, from false positive rates typical of RT-PCR assays of RNA viruses raises questions about the usefulness of mass testing; and indicates that across a broad range of likely prevalences, positive test results are more likely to be wrong than are negative results, contrary to public health advice about SARS-CoV-2 testing. There are myriad clinical and case management implications. Failure to appreciate the potential frequency of false positives and the consequent unreliability of positive test results across a range of scenarios could unnecessarily remove critical workers from service, expose uninfected individuals to greater risk of infection, delay or impede appropriate medical treatment, lead to inappropriate treatment, degrade patient care, waste personal protective equipment, waste human resources in unnecessary contact tracing, hinder the development of clinical improvements, and weaken clinical trials. Measures to raise awareness of false positives, reduce their frequency, and mitigate their effects should be considered.

A clinical evaluation of various delta check methods.

1981 ◽  
Vol 27 (1) ◽  
pp. 5-9 ◽  
Author(s):  
L A Wheeler ◽  
L B Sheiner
Keyword(s):  
Clinical Evaluation ◽  
False Positive ◽  
Continuous Flow ◽  
False Positives ◽  
Anion Gap ◽  
Creatinine Ratio ◽  
Test Results ◽  
Subsequent Test ◽  
Flow Test ◽  
The Cost

Abstract To evaluate the performance of delta check techniques, we analyzed 707 unselected pairs of continuous-flow test results, using three different delta check methods. If any of the test results (plus the urea nitrogen/creatinine ratio and the anion gap) failed one of the checks, the reason for the failure was sought by examining subsequent test results, retesting specimens, and (or) reviewing te patient's chart. Each delta check failure was accordingly classified as a true or false positive. The percentage of positives we judged to be true positives ranged from 5 to 29%. Each of the three methods had test types with low and high percentages of true positives. We conclude that with the delta check methods one can detect errors otherwise overlooked, but at the cost of investigating many false positives, because, in the population we studied, disease processes or therapy often caused large changes in a series of test results for a patient.

scholarly journals Follow-Up SARS-CoV-2 PCR Testing Outcomes From a Large Reference Lab in the US

2021 ◽  
Vol 9 ◽  
Author(s):  
Adam Sullivan ◽  
David Alfego ◽  
Brian Poirier ◽  
Jonathan Williams ◽  
Dorothy Adcock ◽  
...  
Keyword(s):  
United States ◽  
Cohort Study ◽  
False Positive ◽  
False Positive Rate ◽  
The United States ◽  
Positive Test ◽  
Test Results ◽  
Rt Pcr ◽  
Positive Rate

By analyzing COVID-19 sequential COVID-19 test results of patients across the United States, we herein attempt to quantify some of the observations we've made around long-term infection (and false-positive rates), as well as provide observations on the uncertainty of sampling variability and other dynamics of COVID-19 infection in the United States. Retrospective cohort study of a registry of RT-PCR testing results for all patients tested at any of the reference labs operated by Labcorp® including both positive, negative, and inconclusive results, from March 1, 2020 to January 28, 2021, including patients from all 50 states and outlying US territories. The study included 22 million patients with RT-PCR qualitative test results for SARS-CoV-2, of which 3.9 million had more than one test at Labcorp. We observed a minuscule <0.1% basal positive rate for follow up tests >115 days, which could account for false positives, long-haulers, and/or reinfection but is indistinguishable in the data. In observing repeat-testing, for patients who have a second test after a first RT-PCR, 30% across the cohort tested negative on the second test. For patients who test positive first and subsequently negative within 96 h (40% of positive test results), 18% of tests will subsequently test positive within another 96-h span. For those who first test negative and then positive within 96 h (2.3% of negative tests), 56% will test negative after a third and subsequent 96-h period. The sudden changes in RT-PCR test results for SARS-CoV-2 from this large cohort study suggest that negative test results during active infection or exposure can change rapidly within just days or hours. We also demonstrate that there does not appear to be a basal false positive rate among patients who test positive >115 days after their first RT-PCR positive test while failing to observe any evidence of widespread reinfection.

scholarly journals Evidence of false-positive results in a commercially available rotavirus assay in the vaccine era, Australia, 2011 to 2012

2013 ◽  
Vol 18 (21) ◽  
Author(s):  
S Ye ◽  
S Roczo-Farkas ◽  
D M Whiley ◽  
S B Lambert ◽  
J Robson ◽  
...  
Keyword(s):  
Real Time ◽  
False Positive ◽  
The Other ◽  
Rt Pcr ◽  
Pcr Assays ◽  
Positive Results ◽  
Commercial Kit

Concerns were raised about specificity of the VIKIA Rota-Adeno immunochromatographic kit. Only 28-37% of samples positive with the VIKIA kit could be confirmed using two real-time RT-PCR assays and three ELISA kits. On re-analysis of a subset of the positive samples, 86% remained positive with the VIKIA kit, however, 90% remained negative in the other assays. In a highly vaccinated population we found a high number of false-positive rotavirus tests with a widely-used commercial kit.

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 Development of three multiplex RT-PCR assays for the detection of 12 respiratory RNA viruses

2005 ◽  
Vol 126 (1-2) ◽  
pp. 53-63 ◽  
Author(s):  
S. Bellau-Pujol ◽  
A. Vabret ◽  
L. Legrand ◽  
J. Dina ◽  
S. Gouarin ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Rt Pcr ◽  
Pcr Assays

Factors Associated with False Negative and False Positive RT-PCR Test Results for COVID-19 Detection

2021 ◽  
Author(s):  
Shirin Hakimi
Keyword(s):  
False Positive ◽  
False Negative ◽  
Great Accuracy ◽  
Test Time ◽  
Test Results ◽  
Rt Pcr ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Relevant Factors

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread rapidly and developed the current pandemic and the stressful lifestyle in addition with extreme pressure on people was the consequence of its increasing mortality rate. Since COVID-19 is highly infectious, it is crucial to diagnose the disease timely and initiate preventive measures to control the epidemic. Therefore, the need for accurate detection of this virus has been increased dramatically. Real-Time reverse-transcription Polymerase Chain Reaction (RT-PCR) tests are considered a gold standard to detect SARS-CoV-2 RNA. Besides, the recent pandemic has posed the most serious challenge in PCR applications to date. Although RT-PCR has great accuracy, some factors can reduce the efficiency of this test. Time of testing and type of sample are typical elements that may cause false negative results. Furthermore, false positive cases would be the result of contamination and unoptimized primers. In this paper, the relevant factors creating false positive and false negative results have been investigated in depth to increase the awareness of clinicians.

scholarly journals Correcting COVID-19 PCR Prevalence for False Positives in the Presence of Vaccination Immunity

2021 ◽  
Author(s):  
Michael Halem
Keyword(s):  
Public Health ◽  
False Positive ◽  
Vaccination Campaign ◽  
False Positive Rate ◽  
Public Health Authority ◽  
Test Results ◽  
Population Prevalence ◽  
Test Population ◽  
Positive Rate ◽  
Pcr Test

Many public health authority reports on COVID-19 cases confound positive test results with population prevalence. As the population prevalence approaches the PCR test false positive rate (FPR), for example during a vaccination campaign, it is necessary to adjust the the raw test results for the false positive rate. This paper provides a technique for estimating the test false positive rate and making the correction to test population prevalence in the absence of accurate and definitive specificity. Using current data providing by the Public Health England as of the most recent complete data, a false positive rate of 1.16% (95% CI 1.09 - 1.23% ) was found for the PHE PCR test for the period 1 January through 29 March 2021. During this period, the test population prevalence is decreasing, starting at a decay rate estimated as 3.0% per day (CI 2.79 - 3.14%). This rate of decay increased to an estimated 14.7% by the end of the period (CI 13.30 - 16.16%) Finally, mean test population prevalence was estimated at 14.3% (CI 13.75 - 14.87%) on 1 January and is estimated to have declined significantly to 0.06% (CI 0.00 - 0.13%). If PCR test positivity are used without the application of the false positive rate, the percent positive PCR tests will eventually "flatline" at the false positive rate, and produce a false positive bias even if test population prevalence should fall to zero.

Detection of nine respiratory RNA viruses using three multiplex RT-PCR assays incorporating a novel RNA internal control transcript

2011 ◽  
Vol 176 (1-2) ◽  
pp. 9-13 ◽  
Author(s):  
Helen Auburn ◽  
Mark Zuckerman ◽  
Simon Broughton ◽  
Anne Greenough ◽  
Melvyn Smith
Keyword(s):  
Internal Control ◽  
Rna Viruses ◽  
Rt Pcr ◽  
Pcr Assays

scholarly journals Who Could Be Blamed in the Case of Discrepant Histology and Serology Results for Helicobacter pylori Detection?

Diagnostics ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 133
Author(s):  
Sabine Skrebinska ◽  
Francis Megraud ◽  
Ilva Daugule ◽  
Daiga Santare ◽  
Sergejs Isajevs ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
False Positive ◽  
Sampling Error ◽  
False Negative ◽  
Eradication Therapy ◽  
Study Data ◽  
False Positives ◽  
Rt Pcr ◽  
Positive Serology ◽  
H Pylori

Background. Discrepancies between histology and serology results for Helicobacter pylori detection could be caused by a variety of factors, including a biopsy sampling error, expertise of the pathologist, natural loss of infection due to advanced atrophy, or a false-positive serology in the case of a previous infection, since antibodies may be present in blood following recovery from the infection. Aims. To identify true H. pylori-positive individuals in discrepant cases by serology and histology using real time polymerase chain reaction (RT-PCR) as a gold standard. Methods. Study subjects with discrepant histology and serology results were selected from the GISTAR pilot study data base in Latvia. Subjects having received previous H. pylori eradication therapy or reporting use of proton pump inhibitors, antibacterial medications, or bismuth containing drugs one month prior to upper endoscopy were excluded. We compared the discrepant cases to the corresponding results of RT-PCR performed on gastric biopsies. Results. In total, 97 individuals with discrepant results were identified: 81 subjects were serology-positive/histology-negative, while 16 were serology-negative/histology-positive. Among the serology-positive/histology-negative cases, 64/81 (79.0%) were false-positives by serology and, for the majority, inflammation was absent in all biopsies, while, in the serology-negative/histology-positive group, only 6.2% were proven false-positives by histology. Conclusions. Among this high H. pylori prevalent, middle-aged population, the majority of discrepant cases between serology and histology were due to false positive-serology, rather than false-negative histology. This confirms the available evidence that the choice of treatment should not be based solely on the serological results, but also after excluding previous, self-reported eradication therapy.

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