Diagnostic yield of repeat testing for SARS-CoV-2: Experience from a large health system in Los Angeles

Abstract

Objective: To determine the diagnostic yield of repeat testing for SARS-CoV-2. Methods: A retrospective analysis was performed of all SARS-CoV-2 test results within the UCLA Health System between March 9th and April 29th, 2020. All patients with repeat test results were identified, and those with discordant results were reviewed. Results: Between March 9th and April 29th, there were 10,165 SARS-CoV-2 test results, of which 630 (6.2%) were positive. Among the 904 patients with repeat test results, 808 (89.4%) were initially negative, and 96 (10.6%) were initially positive. Among the 808 patients with an initial negative test, 15 (1.9%) subsequently tested positive. Eleven cases with an initial negative SARS-CoV-2 test and without a known prior positive SARS-CoV-2 test were reviewed; 6 were employed as healthcare workers, and 10 were positive on the second test. Conclusions: We found a low diagnostic yield of repeat testing for SARS-CoV-2 in our health system. Repeat testing might prove useful in certain clinical scenarios, such as in healthcare workers, when symptoms develop after a negative test, and in hospitalized patients with a high clinical suspicion of COVID-19.

Keywords

• SARS-CoV-2
• COVID-19
• SARS-CoV-2 RT-PCR
• Diagnosis
• Diagnostic testing