key: cord-0935471-ch1honib
authors: Shakir, S. M.; Barker, A. P.; Hillyard, D. R.; Gilmore, N.; Barrett, J. W.; Orlandi, R. R.; Hanson, K. E.
title: Combined Self-Collected Anterior Nasal and Oropharyngeal Specimens versus Provider-Collected Nasopharyngeal Swabs for the Detection of SARS-CoV-2
date: 2020-12-17
journal: J Clin Microbiol
DOI: 10.1128/jcm.02291-20
sha: f4c4af367ecbe598fba2209651e112424239ca9b
doc_id: 935471
cord_uid: ch1honib

The U.S. Food and Drug Administration (FDA) guidance and Centers for Disease Control interim guidelines for SARS-CoV-2 testing lists patient self-collected anterior nares swab (ANS) as an acceptable alternative to the standard healthcare provider (HCP)-collected nasopharyngeal swab (NPS) (1, 2).….

T he U.S. Food and Drug Administration (FDA) and Centers for Disease Control interim guidelines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing list the patient self-collected anterior nares swab (ANS) as an acceptable alternative to the standard health care provider (HCP)-collected nasopharyngeal swab (NPS) (1, 2). Self-collected ANS minimizes HCP exposure to infectious aerosols, thus reducing the need for high-level personal protective equipment. Self-collection using ANS may also be more comfortable for the patient. However, published reports have observed variable ANS sensitivities compared to NPS (3) (4) (5) . We previously observed that self-collected ANS missed 15% of positive detections compared to NPS or saliva (6) and hypothesized that self-collected swabs from multiple anatomic sites may improve diagnostic sensitivity.

We performed a prospective study of self-collected oropharyngeal swab (OPS) combined with self-collected ANS versus HCP-collected NPS. After providing informed consent, adult patients presenting to a drive-through test center with symptoms suggestive of COVID-19 were instructed first to swab their throat with one swab and then to swab both anterior nares with a second swab. The HCP-collected NPS was obtained last. The oropharyngeal and anterior nares swabs were placed in a single tube with 3 ml sterile 1ϫ phosphate-buffered saline (PBS). Either foam swabs or spun swabs were used for the combined collections. A flocked swab placed in 3 ml 1ϫ PBS was used for NPS sampling. Specimens were tested by any one of several FDA Emergency Use Authorization (EUA) nucleic acid amplification tests (NAAT) currently in use in our laboratory, including the cobas SARS᎑CoV᎑2 (Roche) assay, Panther Fusion SARS-CoV-2 (Hologic) assay, or the Aptima SARS-CoV-2 (Hologic) assay.

Paired Table 1 . In all, 78.6% (332/423) of OPS-ANS collections were spun swabs and 21.3% (90/423) were foam swabs. There were 4 patients (0.95%) positive for SARS-CoV-2 by NPS only. In addition, a single patient was positive by OPS-ANS spun swab alone. Paired OPS-ANS and NPS samples with residual volume were retested with the Panther Fusion SARS-CoV-2 assay for resolution of discrepancies. Samples with initial "detected" results repeated as low positives with threshold cycle (C T ) values of Ͼ34 (data not shown).

In conclusion, self-collected patient OPS and ANS use is logistically feasible and analytically equivalent to HCP-collected NPS use for the detection of SARS-CoV-2. Our results correlate with published observations from other groups (7, 8) . A multisite collection strategy, however, depends on the availability of swab supplies. We did not assess using a single swab for the OPS-ANS dual collection, which could be considered if swab supplies are expected to be limiting. Potential explanations for observed discrepancies include inadequate collection technique, use of nonflocked swabs for the OPS-ANS collection, and/or low virus loads near the limit of detection of the respective EUA assays. An imbalance in the numbers of spun versus foam swabs also precluded conducting an adequate comparison of swab types. Despite these limitations, combined OPS-ANS samples represent a useful and practical approach for SARS-CoV-2 testing. 

Food and Drug Administration. 2020. FAQs on diagnostic testing for SARS-CoV-2

Interim guidelines for collecting, handling, and testing clinical specimens for COVID-19

Assessment of sensitivity and specificity of patient-collected lower nasal specimens for sudden acute respiratory syndrome coronavirus 2 testing

Nasal swab sampling for SARS-CoV-2: a convenient alternative in times of nasopharyngeal swab shortage

Swabs collected by patients or health care workers for SARS-CoV-2 testing

Self-collected anterior nasal and saliva specimens versus healthcare worker-collected nasopharyngeal swabs for the molecular detection of SARS-CoV-2

A combined oropharyngeal/nares swab is a suitable alternative to nasopharyngeal swabs for the detection of SARS-CoV-2

Combined throat/nasal swab sampling for SARS-CoV-2 is equivalent to nasopharyngeal sampling

We thank the ARUP Institute for Clinical and Experimental Pathology for their support.