Log viral loads by NP PCR according to the RDT brand used.
The diagnostic performance of NP PCR and saliva PCR were equivalent: sensitivity was 95.7% (93.1–97.5%) for saliva compared to NP PCR and 96.5% (94.1–98.1%) for NP compared to saliva PCR, with an intraclass correlation coefficient (ICC) of 0.935 (95%CI [0.926–0.943]) between these tests.When using patients with any test positive as reference, sensitivity was 84.9% (81.0–88.3%) for RDT, 95.8% (93.3–97.6%) for saliva PCR, and 96.6% (94.3–98.2%) for NP PCR. The difference was not significant between NP PCR and saliva PCR test status (p = 0.71), but was so between RDT and NP PCR or saliva PCR (p<0.001). Specificity of RDT was 100% (99.3–100%), which means that there was no false positive RDT. In two instances, RDT was positive, and NP PCR was negative, but the saliva PCR was positive with viral loads of 4.0x10