The use of gargling (also called ‘throat washings’) and oropharyngeal swabs with marginally lower dilutions can be considered for the diagnosis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, a study in Viruses journal revealed. Real-time reverse-transcription Polymerase Chain Reaction (qRT PCR) is utilized to detect SARS-CoV-2 from the respiratory tract samples. This study by Florian Hitzenbichler et al. compared three sampling methods-gargling, nasopharyngeal swabs, and oropharyngeal swabs for the same.

Overall, 102 samples from 34 individuals in the age group 22–83 years with SARS-CoV-2 infection were evaluated by RT-qPCR with definite quantification. The median concentration and diagnostic sensitivities for nasopharyngeal swabs, oropharyngeal swabs, and throat washings are illustrated in the table below:

Noteworthy concentration differences were found between nasopharyngeal swabs and gargling (P = 0.019). Saliva was obtainable from 21 individuals (median 3.4×103 copies per mL).

The presence of just moderately lesser viral loads in oropharyngeal swabs and gargling denoted that they can be regarded as a substitute to nasopharyngeal swabs for COVID-19. Also, gargling could permit self-sampling in patients, thus lowering the infection risk for healthcare staff, Florian Hitzenbichler mentioned.