Equal Performance of Self-Collected and Health Care Worker-Collected Pharyngeal Swabs for Group A Streptococcus Testing by PCR

Abstract

A process employing patient-or parent-collected pharyngeal swabs for group A Streptococcus (GAS) testing would expedite diagnosis and treatment, reduce patient exposure to the health care setting, and decrease health care costs. Our aim was to determine the concordance between patient-or parent-collected (self-collected) and health care worker (HCW)-collected pharyngeal swabs for detection of GAS by PCR. From 9 October 2012 to 21 March 2013, patients presenting with a sore throat meeting criteria for GAS testing and not meeting criteria for severe disease were offered the opportunity to collect their own pharyngeal swab. The HCW also collected a swab. Paired swabs were tested by GAS real-time PCR, allowing semiquantitative comparisons between positive results. Of the 402 participants, 206 had a swab collected by the patient and 196 a swab collected by the parent. The percent positivity results were 33.3% for HCW-collected swabs and 34.3% for self-collected swabs (P ‫؍‬ 0.41). The overall concordance between the two collection strategies was 94.0% (95% confidence interval [CI], 91.3 to 96.0). Twenty-four of the paired swabs had discordant results, with 10 and 14 positives detected only with the HCW-and self-collected swabs, respectively (P ‫؍‬ 0.41). The person collecting the swab in the self-collected arm, the order of collection, and prior swab collection training did not influence results. Among the 124 specimens that were positive by both collection methods, the amount of GAS DNA was higher in the self-collected versus the HCW-collected swabs (P ‫؍‬ 0.008). Self-collected pharyngeal swabs provide a reliable alternative to HCW collection for detection of GAS and offer a strategy for improved health care delivery.A cute pharyngitis is a common illness, responsible for an estimated 15 million ambulatory care visits in the United States in 2006 (1). Between 30% and 60% of acute pharyngitis cases are thought to be of viral origin (2) followed in number by bacterial causes. Group A Streptococcus (GAS) is the most common bacterial agent of acute pharyngitis, accounting for 20% to 30% of cases in children and 5% to 15% of cases in adults (3, 4).Group A streptococcal pharyngitis is typically self-limiting but can be associated with significant, preventable morbidity, especially in young children and adolescents (5). Among the most serious complications are mastoiditis, peritonsillar abscess, pneumonia, bacteremia, and meningitis. Primary infection can also trigger rheumatic fever and poststreptococcal glomerulonephritis (2). For this reason, GAS pharyngitis is commonly treated with antibiotics to limit disease transmission, ameliorate symptoms, and minimize complications (2, 3).Transmission of GAS pharyngitis usually occurs through mucosal contact with respiratory droplets from infected individuals. High transmission rates have been reported in settings with close person-to-person contact, such as homes and schools, and may also occur in health care settings. In one study, over 40% of families with a confirmed case of...

Report from the American Society for Microbiology COVID-19 International Summit, 23 March 2020: Value of Diagnostic Testing for SARS–CoV-2/COVID-19

“…The most common sample types being tested are swabs taken from the nasopharynx and/or oropharynx, with the former considered somewhat more sensitive than the latter (2); if both are collected, the two swabs may be combined and tested simultaneously in a single reaction to conserve reagents. Today, health care professionals collect these swabs; however, evidence suggests that patients or parents (in the case of young children) might be able to collect their own swabs (3,4). Following collection, swabs are placed into a liquid to release virus/viral RNA from the swabs into solution.…”

Development of a Laboratory-safe and Low-cost Detection Protocol for SARS-CoV-2 of the Coronavirus Disease 2019 (COVID-19)

“…The detailed pharyngeal swab procedure was established and adopted based on the previous report describing the equal performance of self-collected and health care worker-collected pharyngeal swabs for Group A Streptococcus testing by PCR [14]. To prevent any possible contact within volunteers and between a volunteer and a health care worker, we adopted the self-collection procedure.…”

SARS-CoV-2 pandemic: a review of molecular diagnostic tools including sample collection and commercial response with associated advantages and limitations

“…Swabs are generally taken from the nasopharynx or oropharynx [169], with a nasopharyngeal sample being more sensitive than oropharyngeal [16,170,171]. Usually, a healthcare worker collects these samples, but it has been shown that the collection can be done at home by the patient [172,173]. Selfsampling reduces the risks to healthcare workers (see "COVID-19 testing models").…”