To Boldly Go Where No Device Has Gone Before: Specimen Self-Collection for the Clinical Laboratory

The indications for and interest in self-collection of specimens, such as blood, saliva, urine, stool, and anogenital specimens, for clinical laboratory testing are vast (especially in the post-pandemic era). A need for innovation, combined with convenience for patients, clinicians, and researchers, opened the doors for a wave of self-collection devices to flood the market in early 2020. Many of the devices discussed in this review are registered by the U.S. Food and Drug Administration (FDA) or have emergency use authorization for diagnostic testing in clinical laboratories. While many self-collection devices were evaluated for collection of specimens for SARS-CoV-2 testing, they can be used to collect samples for many other serologic, molecular, or other diagnostic methods following completion of necessary laboratory validation studies. The advantages of these devices, such as convenience and access, must be balanced with added cost, challenges of specimen stability, and manual processing in the laboratory, all of which are discussed in this review.

Evaluation of Self-Collected Midturbinate Nasal Swabs and Saliva for Detection of SARS-CoV-2 RNA.

Rapid and accurate diagnostic testing is essential to bring the ongoing COVID-19 pandemic to an end. As the demand for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing continues to increase amid supply shortages, many laboratories have investigated the use of sources other than nasopharyngeal (NP) swabs. Saliva and midturbinate (MT) nasal swabs are attractive alternatives, as they allow for self-collection and are well accepted by patients. Saliva also requires limited consumables. We compared the performance of health care provider-collected NP swabs, patient-collected MT swabs, and patient-collected saliva specimens for SARS-CoV-2 detection using a laboratory-developed PCR assay that had received Emergency Use Authorization by the FDA. Of 281 total evaluable samples, 33 (11.7%) NP swabs, 33 (11.7%) MT swabs, and 32 (11.4%) saliva specimens were positive for SARS-CoV-2 following resolution of discordant results. Compared to NP swabs, saliva exhibited a sensitivity of 90.9% (30/33) and specificity of 99.2% (246/248), while patient-collected MT swabs exhibited a sensitivity of 93.9% (31/33) and specificity of 99.2% (246/248). When comparing to the consensus standard, the sensitivity was found to be 100% (31/31) for both NP and MT swabs and 96.8% (30/31) for saliva specimens, while specificity was the same in both NP swabs and saliva specimens (98.8% [247/250]) and 99.2% (248/250) for MT swabs. Pretreatment of saliva with proteinase K and heating for 15 min prior to extraction reduced the invalid rate from 26.7% (52/195) to 0% (0/195). These data show that midturbinate nasal swabs and saliva are suitable sources for self-collection in individuals who require routine monitoring for SARS-CoV-2 infection.