Alliance for Pandemic Preparedness

May 19, 2020

Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure

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  • Kucirka et al. found that the probability of a false negative SARS-CoV-2 test result using RT-PCR varied significantly over the disease course. Among 1,330 patients, the false negative rate was lowest between symptom onset (38% false negative rate) and 3 days following symptom onset (20% false negative rate).
  • Prior to symptom onset, patients had a high probability of receiving a false negative test result (100% at4 days prior to symptom onset, decreasing to 67% at1 day prior to symptom onset). The probability of receiving a false negative increased again 4 days after symptom onset (21%) to 16 days following symptom onset (66%).
  • These findings suggest that RT-PCR test results for SARS-CoV-2 should be interpreted cautiously, particularly early in the course of infection. Infection should not be ruled out on the basis of RT-PCR alone if clinical and epidemiological evidence is strongly suggestive of SARS-CoV-2 infection.
Kucirka et al. (May 13,2020). Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure. Annals of Internal Medicine. https://doi.org/10.7326/M20-1495