Common Coronavirus Disease 2019 Upper Respiratory Tract Sampling Techniques in Children

Background: during covid-19 pandemic, most studies have focused on sampling technique in adults. considering the need to be aware of the effectiveness and evaluation of sampling methods in children, we have motivated a search for introducing and performing sampling techniques, especially upper respiratory tract sampling inchildren. we systematically reviewed the literature to understand the performance of different sampling methods in children in covid-19. methods: we systematically reviewed pubmed, google scholar, medrxiv, and biorxiv (last retrieval august 1st, 2021) for comparative studies of deferent sampling techniques by using the search keywords including: children, pediatric sampling, nasopharyngeal, covid-19, oropharyngeal, swabs, sars, cov2. 8 relevant manuscripts were sourced from a total of 4852 search results. results: nasopharyngeal (np) swabs testing significantly had higher positivity rate over oropharyngeal swab in detecting sars-cov-2. nasal swab has a low sensitivity in detecting sarscov-2 in children when referred to the nasopharyngeal aspiration (npa), whereas its specificity is high. therefore, npa can be as the gold standard for detection of sars-cov-2. conclusion: saliva is not a useful for diagnosing covid-19 in children. negative nasopharyngeal and oropharyngeal swabs do not rule out covid-19 and in patients with strong clinical suspicion, and bronchoalveolar lavage (bal) can be helpful.