Comparison of Mid-turbinate Nasal Swabs, Saliva, and Nasopharyngeal Swabs for SARS-CoV-2 Reverse Transcription-Polymerase Chain Reaction Testing in Pediatric Outpatients

Arch Pathol Lab Med. 2022 Sep 1;146(9):1056-1061. doi: 10.5858/arpa.2021-0625-SA.

Abstract

Context.—: Diagnostic testing for SARS-CoV-2 in symptomatic and asymptomatic children remains integral to care, particularly for supporting return to and attendance in schools. The concordance of SARS-CoV-2 detection in children, using various specimen types, has not been widely studied.

Objective.—: To compare 3 sample types for SARS-CoV-2 polymerase chain reaction (PCR) testing in children, collected and tested at a single facility.

Design.—: We prospectively recruited 142 symptomatic and asymptomatic children/young adults into a sample comparison study performed in a single health care system. Each child provided self-collected saliva, and a trained health care provider collected a mid-turbinate nasal swab and nasopharyngeal (NP) swab. Specimens were assayed within 24 hours of collection by using reverse transcription-polymerase chain reaction (RT-PCR) to detect SARS-CoV-2 on a single testing platform.

Results.—: Concurrently collected saliva and mid-turbinate swabs had greater than 95% positive agreement with NP swabs when obtained within 10 days of symptom onset. Positive agreement of saliva and mid-turbinate samples collected from children with symptom onset >10 days prior, or without symptoms, was 82% compared to NP swab samples. Cycle threshold (Ct) values for mid-turbinate nasal samples more closely correlated with Ct values from NP samples than from saliva samples.

Conclusions.—: These findings suggest that all 3 sample types from children are useful for SARS-CoV-2 diagnostic testing by RT-PCR, and that concordance is greatest when the child has had symptoms of COVID-19 within the past 10 days. This study provides scientific justification for using sample types other than the NP swab for SARS-CoV-2 testing in pediatric populations.

MeSH terms

  • COVID-19 Testing
  • COVID-19* / diagnosis
  • Child
  • Humans
  • Nasopharynx
  • Outpatients
  • Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Reverse Transcription
  • SARS-CoV-2* / genetics
  • Saliva
  • Specimen Handling / methods
  • Turbinates
  • Young Adult