Clinical Performance of SARS-CoV-2 Molecular Tests.

TitleClinical Performance of SARS-CoV-2 Molecular Tests.
Publication TypeJournal Article
Year of Publication2020
AuthorsGreen DA, Zucker J, Westblade LF, Whittier S, Rennert H, Velu P, Craney A, Cushing M, Liu D, Sobieszczyk ME, Boehme AK, Sepulveda JL
JournalJ Clin Microbiol
Date Published2020 Jul 23
KeywordsAdolescent, Adult, Aged, Aged, 80 and over, Betacoronavirus, Child, Child, Preschool, Clinical Laboratory Techniques, Coronavirus Infections, COVID-19, COVID-19 Testing, Diagnostic Tests, Routine, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, New York, Pandemics, Pneumonia, Viral, Predictive Value of Tests, SARS-CoV-2, Sensitivity and Specificity, Viral Load, Young Adult

Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the gold standard for diagnosis of coronavirus disease 2019 (COVID-19), but the clinical performance of these tests is still poorly understood, particularly with regard to disease course, patient-specific factors, and viral shedding. From 10 March to 1 May 2020, NewYork-Presbyterian laboratories performed 27,377 SARS-CoV-2 molecular assays from 22,338 patients. Repeat testing was performed for 3,432 patients, of which 2,413 had initial negative and 802 had initial positive results. Repeat-tested patients were more likely to have severe disease and low viral loads. The negative predictive value of the first-day result among repeat-tested patients was 81.3% The clinical sensitivity of SARS-CoV-2 molecular assays was estimated between 58% and 96%, depending on the unknown number of false-negative results in single-tested patients. Conversion to negative was unlikely to occur before 15 to 20 days after initial testing or 20 to 30 days after the onset of symptoms, with 50% conversion occurring at 28 days after initial testing. Conversion from first-day negative to positive results increased linearly with each day of testing, reaching 25% probability in 20 days. Sixty patients fluctuated between positive and negative results over several weeks, suggesting that caution is needed when single-test results are acted upon. In summary, our study provides estimates of the clinical performance of SARS-CoV-2 molecular assays and suggests time frames for appropriate repeat testing, namely, 15 to 20 days after a positive test and the same day or next 2 days after a negative test for patients with high suspicion for COVID-19.

Alternate JournalJ Clin Microbiol
PubMed ID32513858
PubMed Central IDPMC7383556
Related Faculty: 
Hanna Rennert, Ph.D. Lars Westblade, Ph.D. Melissa Cushing, M.D. Priya Velu, M.D., Ph.D.


Pathology & Laboratory Medicine 1300 York Avenue New York, NY 10065 Phone: (212) 746-6464
Surgical Pathology: (212) 746-2700