Saliva for Detection of SARS-CoV-2

To the Editor: Wyllie and colleagues (Sept. 24 issue) 1 provide helpful data regarding the use of saliva samples for the detection of SARS-CoV-2 by reverse-transcriptase polymerase chain reaction (RT-PCR). We would like to call attention to one detail. For most of the PCR data, absolute quantification was applied, which provided data on the viral load of the samples in units of copies per milliliter. Wyllie et al. did so using a formula that was based on a standard curve that was generated by measuring serial dilutions of known quantities of SARS-CoV-2 RNA transcripts, which was done during a previous study. 2 . . .