Epidemiological application of the cycle threshold value of RT-PCR for estimating infection period in cases of SARS-CoV-2

Epidemiological control of coronavirus disease 2019 (COVID-19) is needed to estimate the infection period confirmed cases and identify potential cases. The present study, targeting for which time COVID-19 symptom onset was disclosed, aimed investigate relationship between intervals (day) from testing cycle threshold (CT) values real-time reverse transcription-polymerase chain reaction. Of cases, those date suspected in epidemiological investigation specifically disclosed were included this study. Interval defined as number days (as by patient) specimen collection testing. A locally weighted regression smoothing (LOWESS) curve applied, with explanatory variables CT (CTR RdRp gene CTE E gene) outcome variables. After finding its non-linear relationship, a polynomial model applied 95% confidence interval CTR interval. application LOWESS 331 patients identified U-shaped according days, both satisfied quadratic days. Active these results investigations would minimize chance failing individuals who are contact thereby reducing transmission virus local communities.