Nasopharyngeal swab collection in the suspicion of Covid-19.

RT-PCR detection of SARS-CoV-2 mRNA on nasopharyngeal swab is the standard for diagnosing active Covid-19 disease in asymptomatic subjects and in symptomatic patients without the typical radiological findings. Nasopharyngeal swabbing appears a trivial procedure, still an inappropriate nasopharyngeal sampling, performed by untrained operators, can be a relevant cause of false negative findings with a clear negative impact on the effort to control the epidemic and, when PPE is not properly used, this can expose healthcare workers and patients to risks of contagion.