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://www.acpjournals.org/doi/abs/10.7326/M20-1495

Over the 4 days of infection before the typical time of symptom onset (day 5), the probability of a false-negative result in an infected person decreases from 100% (95% CI, 100% to 100%) on day 1 to 67% (CI, 27% to 94%) on day 4, although there is considerable uncertainty in these numbers. On the day of symptom onset, the median false-negative rate was 38% (CI, 18% to 65%) (Figure 2, top). This decreased to 20% (CI, 12% to 30%) on day 8 (3 days after symptom onset) then began to increase again, from 21% (CI, 13% to 31%) on day 9 to 66% (CI, 54% to 77%) on day 21.