The effect of q-RT-PCR analysis method on saline gargle samples in SARS-CoV-2 clinical diagnostic methods

COVID‑19 is a devastating disease, and its control is difficult due to its high transmissibility rate and a long incubation average period (6.4 days). Additionally, more than half of the infected patients were asymptomatic young people or children. The asymptomatic virus transmission is the actual challenge to controlling the disease. Because of limited treatment options, diagnosis techniques have been the first focus all over the world, involving q-RT-PCR as a gold standard, serological tests, point of care studies, or RT-LAMP. Generally, nasopharyngeal, and oropharyngeal samples are preferred clinically as sources. However, alternative sources are being researched, particularly for healthcare professionals who have difficulty taking samples, patients who are afraid of giving samples, and pediatric patients. Herein, physiological saline has been utilized to offer an alternative source besides the swab samples for use in q-RT-PCR. In this study, 212 randomly chosen patients’ samples were studied, and we evaluated the concordance and accurate q-RT-PCR results in two different sources, obtained from swab and gargle samples of patients. Herein, physiological saline is utilized, which is widely used medically as a recommended irrigating and wound dressing solution. We obtained in our experiments with this method, the confidence interval determines 74.50% positivity when compared to the routine q-RT-PCR procedure as summarized. In addition, when only the gargle sampling method is studied in low-income countries, the cost of testing for COVID-19 will decrease significantly. Because this method does not require vNAT or VTM transport solution sterile swab sticks as shown. The plastic container with a lid in which the patient can gargle with SF and spit it out is an ideal method for this. Additionally, it provides a great cost-benefit in low-income countries.