Epidemiological Correlates of Polymerase Chain Reaction Cycle Threshold Values in the Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) salvatore2020epidemiological

This study was conducted in Utah and Wisconsin between 23 March and 13 May 2020, with testing data collected during a prospective household transmission investigation of outpatient and mild coronavirus disease 2019 cases.

Analytes

N1_probe

SARS-CoV-2 RNA genome copy concentration calculated from evaluation of both N1 probe. Results were considered positive if signals were detected (Ct < 40) for the RP, N1, and N2 genes. Results were classified as ‘not detected’ if RP was detected but no signal was observed (Ct >= 40) from either N1 or N2. Results were classified as inconclusive if RP was detected (Ct < 40) and either N1 or N2 was detected (but not both). Results were classified as invalid if no RP was detected in the sample. Any specimens for which results were inconclusive were retested; specimens which produced inconclusive results after retesting were excluded from the analysis (n = 17 specimens from 6 participants). Ct values for amplification of both viral targets (N1 and N2 probes). But for further analysis, the author focused on N1 probe

Biomarker: SARS-CoV-2
Specimen: nasopharyngeal swab
Units: cycle threshold
Gene target: N1
Participants: 93
Negative samples: 66
Positive samples (not quantifiable): 0
Quantifiable samples: 157
Limit of quantification: unknown
Limit of detection: 40