Borderline SARS-COV-2 patients: the trace behind.

BACKGROUND: Effective and precise SARS-CoV-2 detection assays are crucial for maintaining regular hospital routines and identifying infected hospital employees and infected patients before hospital admission. Inconclusive PCR test results of potentially infectious borderline SARS-CoV-2 patients can confuse clinicians and delay appropriate infection control.

OBJECTIVES AND STUDY DESIGN: In this retrospective study, we followed up borderline SARS-CoV-2 patients tested (from the second sample with the same method) at the Clinical Department of Clinical Microbiology. We aimed to determine the positivity conversion ratio within seven days after inconclusive PCR test results.

RESULTS: Out of 247 borderline patients, who were resampled and retested in the same laboratory, 60 patients (29,4%) showed conversion of the borderline viral load (inconclusive RT PCR test) to a positive RT PCR test result.

CONCLUSIONS: Our results highlight the need for retesting of borderline patients with inconclusive SARS-CoV-2 results. Follow-up testing of inconclusive PCR results within seven days can identify additional positive results and reduce the potential risk of intrahospital transmission.