A Comparison of Diagnostic Accuracy of a Rapid Antigen Detection Test in Screening for Group A Streptococcal Throat Infection Between 3- to 10-Year-Old (Children and Preadolescents) and 11- to 21-Year-Old (Adolescents).

Introduction Pharyngitis is one of the most common childhood diseases worldwide. We intended to compare the performance of one such rapid antigen detection test (RADT) using lateral flow immunoassay technique, between 3- to 10-year-old (children and preadolescent) and 11- to 21-year-old (adolescents). Methods Children and adolescents attending the pediatric ED with complaints of throat pain and signs of pharyngeal and tonsillar inflammation were tested by both the RADT and throat culture (TC) directed towards group A streptococcal (GAS) between April and June of 2016. The prevalence, sensitivity (SN), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) were calculated against throat culture, the gold standard for the diagnosis of GAS pharyngitis. Comparisons between the two age groups were made using the Chi-square test Results Of 202 patients, 123 (61%) patients were between 3-11 and 79 (39%) between 11-21 years of age. A positive throat culture was recorded in 56 patients yielding an overall prevalence of GAS pharyngitis at 28%. For the whole sample, the screening RADT had an SN, SP, PPV and NPV of 79%, 90%, 75%, and 92%, respectively. Also, there was no statistically significant difference between the two groups in terms of SN, SP, PPV and NPV. Conclusion The RADT in use at our institution, performed comparable to studies reported in the literature using a similar technique in both preadolescent and adolescent age groups.