Comparable Specimen Collection from Both Ends of At-Home Midturbinate Swabs

At-home respiratory specimen collection for pathogen testing enables community sampling. Furthermore, it requires neither a health care worker’s time nor personal protective equipment, and symptomatic individuals can continue to self-isolate. However, questions remain as to whether unsupervised upper respiratory specimen collection by individuals in their homes reliably produce specimens that are of high enough quality for pathogen testing. From October 2019 through May 2020, the Seattle Flu Study (1, 2) and the greater Seattle Coronavirus Assessment Network (SCAN; scanpublichealth.org) screened 16,785 midturbinate swabs that were self-collected by participants at home for respiratory pathogens. The at-home kits contained a flocked, midturbinate swab (Copan 56380CS01 or 56750CS01), either adult or pediatric, a tube of universal transport media (UTM), and instructions on how to self-collect a specimen or collect a specimen for a child and return it to the lab (2). Of the kits distributed to individuals in the Seattle metropolitan area, most resulted in swabs returned appropriately according to the instructions in the kit, but 138/16,785 (0.8%) kits were returned to the lab with the swab handle in the UTM tube rather than the swab itself. The swab handle is nontapered, hard plastic with decreased surface area compared with the flocked end of the swab (Fig. 1A). We were puzzled by this phenomenon and sought to evaluate whether handle-collected specimens were comparable to flocked swabs themselves for molecular pathogen detection. We also assessed demographic covariates associated with errors in swab collection.