“…By fixing a reference standard to one anatomic site to assess new tests, this may increase the risk of determining that a new assay performs worse than it truly does, typically in the direction that the new assay is less specific because it identifies "unconfirmed infections." Less commonly the new assay may be found to be less sensitive if the single reference comparator detects clinically insignificant infections beyond the relevant clinical period of infection.Studies have found that when comparing nasopharyngeal specimens to other anatomic sites (nasal and oral fluid or saliva), infected-persons were missed by nasopharyngeal specimens(5)(6)(7). Additionally, in one study that detected SARS-CoV-2 RNA in salivaon February 1, 2021 by guest http://jcm.asm.org/ Downloaded from specimens from asymptomatic persons with 9 matched nasopharyngeal specimens to those samples, 7 nasopharyngeal specimens did not have detectable SARS-CoV-2.All 13 individuals tested positive, however, for COVID-19 on repeat nasopharyngeal swab testing(5).…”