The role of mouthwash sampling in SARS-CoV-2 diagnosis.

Abstract

BACKGROUND:

The current practice of COVID-19 diagnosis worldwide is the use of oro-nasopharyngeal (ONP) swabs. Our study aim was to explore mouthwash (MW) as an alternative diagnostic method, in light of the disadvantages of ONP swabs.

METHODS:

COVID-19 outpatients molecular-confirmed by ONP swab were repeatedly examined with ONP swab and MW with normal saline (0.9%). Other types of fluids were compared to normal saline. The Cq values obtained with each method were compared.

RESULTS:

Among 137 pairs of ONP swabs and MW samples, 84.6% (116/137) of ONP swabs were positive by at least one of the genes (N, E, R). However MW detected 70.8% (97/137) of samples as positive, which means 83.6% (97/116) out of positive ONP swabs, missing mainly Cq value > 30. In both methods, the N gene was the most sensitive one. Therefore, MW samples targeting N gene, which was positive in 95/137 (69.3%), are comparable to ONP swabs targeting E and R genes which gave equal results-95/137 (69.3%) and 90/137 (65.7%), respectively. Comparing saline MW to distilled water gave equal results, while commercial mouth-rinsing solutions were less sensitive.

CONCLUSIONS:

MW with normal saline, especially when tested by N gene, can effectively detect COVID-19 patients. Furthermore, this method was not inferior when compared to R and E genes of ONP swabs, which are common targets in many laboratories around the world.

• Authors: Asaf Biber, Dana Lev, Michal Mandelboim, Yaniv Lustig, Geva Harmelin, Amit Shaham, Oran Erster, Eli Schwartz
• Journal: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology (Eur J Clin Microbiol Infect Dis) Vol. 40 Issue 10 Pg. 2199-2206 (Oct 2021) ISSN: 1435-4373 [Electronic] Germany
• PMID: 34342767 (Publication Type: Clinical Trial, Journal Article)
• Copyright: © 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Chemical References

• Mouthwashes

Topics

• Adult
• Aged
• COVID-19 (diagnosis, virology)
• COVID-19 Nucleic Acid Testing
• Female
• Humans
• Male
• Middle Aged
• Mouthwashes (analysis)
• Prospective Studies
• SARS-CoV-2 (genetics, isolation & purification)
• Saliva (chemistry, virology)
• Young Adult