Researchers from the University of Missouri School of Medicine have created and tested a method to identify potential false-positive COVID-19 results. The method, as used at MU Health Care, could assist other labs in avoiding unnecessary testing and testing of people who are not actually infected.
COVID-19 testing is a useful tool in managing the virus in the event of an outbreak. The most frequently used method is reverse transcriptase polymerase chains reaction (RTPCR) testing. But while this type of test is regarded to be reliable but it can be associated with a small percentage of false positives, which are most easily identified in non-exposed, symptomatic patients.
False positive diagnoses could have serious implications for the treatment of patients. False positives could result in improper quarantine, delay in any other medical treatment needed or transfer to a COVID-19 ward.”
Lester Layfield, MD, professor of pathology and anatomical sciences and director of the Molecular Diagnostics Laboratory
Layfield developed a procedure to ensure that positive results are accurate. It also includes repeated tests for all positive results.
Layfield and his team of researchers implemented the quality control protocol in September 2020. 24,717 RTPCR tests were conducted over an eight-week span. Of those, 6,251 came from asymptomatic patients. In that group, 288 samples initially gave a positive result. A second test revealed 20 of them to be false positives.
Layfield claimed that retesting positive results from patients who were symptomatic revealed technologist mistakes and contamination from positive specimens found in nearby wells. “This study should alert the testing laboratories to the possibility of false positive COVID-19 test results.”
Layfield, L.J., et al. (2021) SARS-CoV-2 detection by reverse transcriptase polymerase chain reaction testing analysis of false positive results and recommendations for quality control measures. Pathology – Research and Practice. doi.org/10.1016/j.prp.2021.153579.
Content Source: https://www.news-medical.net/news/20211117/New-method-to-identify-potential-false-positive-COVID-19-results.aspx