Comparison of Nasopharyngeal Swab and Nasopharyngeal Aspiration in Adults for SARS-CoV-2 Identification Using Reverse Transcription Polymerase Chain Reaction

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J Med Virol. 2021 Jul 31. doi: 10.1002/jmv.27250. Online ahead of print.


OBJECTIVE: To compare RT-PCR results of nasopharyngeal aspiration (NA) and nasopharyngeal swab (NS) samples in the diagnosis of COVID-19.

METHODS: NS was obtained with a dacron swab and NA was performed by aspiration cannula. The sampling was performed by an otolaryngologist to ensure standardized correct sampling from the nasopharynx. The RT-PCR was performed for the detection of SARS-CoV-2. The level of agreement between the result of NA and NS samples for each patient was analyzed. The Ct values were compared.

RESULTS: Thirty-three patients were enrolled in the study with a mean age of 56,3 years. Thirteen subjects resulted negative with both NS and NA; 20 subjects resulted positive with NA and 18 subjects resulted positive with NS. The mean values of Ct for NA samples and NS samples were 24,6±5,9 and 24±6,7, respectively. There was no statistical difference between Ct values of NA and NS samples (p=0,48).

CONCLUSION: RT-PCR for SARS-Cov2 performed with NA sample and NS sample showed a strong correlation regarding the positivity /negativity and the Ct values. This article is protected by copyright. All rights reserved.

PMID:34331714 | DOI:10.1002/jmv.27250