Nasal swab as an alternative specimen for the detection of severe acute respiratory syndrome coronavirus 2

Abstract

Abstract Background and Aims The coronavirus disease 2019 (COVID‐19) has brought serious threats to public health worldwide. Nasopharyngeal, nasal swabs, and saliva specimens are used to detect severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). However, limited data are available on the performance of less invasive nasal swab for testing COVID‐19. This study aimed to compare the diagnostic performance of nasal swabs with nasopharyngeal swabs using real‐time reverse transcription polymerase chain reaction (RT‐PCR) considering viral load, onset of symptoms, and disease severity. Methods A total of 449 suspected COVIDCOVID‐19 individuals were recruited. Both nasopharyngeal and nasal swabs were collected from the same individual. Viral RNA was extracted and tested by real‐time RT‐PCR. Metadata were collected using structured questionnaire and analyzed by SPSS and MedCalc software. Results The overall sensitivity of the nasopharyngeal swab was 96.6%, and the nasal swab was 83.4%. The sensitivity of nasal swabs was more than 97.7% for low and moderate Ct values. Moreover, the performance of nasal swab was very high (>87%) for hospitalized patients and at the later stage >7 days of onset of symptoms. Conclusion Less invasive nasal swab sampling with adequate sensitivity can be used as an alternative to nasopharyngeal swabs for the detection of SARS‐CoV‐2 by real‐time RT‐PCR.

Keywords

• COVID‐19
• nasal swab
• nasopharyngeal swab
• real time RT‐PCR
• SARS‐CoV‐2
• sensitivity