RT-PCR test results may show inaccurate results if not taken or read properly. No evidence suggests that 56 percent of cases are not infectious.
The British Society for Immunology reported that PCR tests have a high accuracy rate when trained laboratory professionals perform. It is a highly sensitive test that can detect the lowest levels of genetic material from a sample. However, the nose and throat swab sampling needs to be done correctly. Sometimes tests can give false-negative results, which can occur between 2 to 29 percent of the time.
Vincent Racaniello, a professor of microbiology and immunology at Columbia University, said there are chances of a false-negative result if the sample is taken incorrectly, Scientific American reported.
World Health Organization notes that careful interpretation of weak positive results is needed in the PCR test. The cycle threshold (Ct) required to detect the virus is inversely proportional to the patient's viral load. The test result must be carefully read, assessing the timing of sample, specimen type, assay specifics, clinical observations, patient history, confirmed status of any contacts, and epidemiological information.
The U.S. Food and Drug Association (FDA) conducted a clinical study to evaluate the performance of the COVID-19 RT-PCR test. A total of 100 individual clinical respiratory samples, 50 nasopharyngeal (NP) swabs, and 50 bronchoalveolar lavages (BALs) were used in the study. After examining the survey, the positive and negative percent agreements between the COVID-19 RT-PCR test and the expected results in NP swabs and BALs have shown accurate results.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.