The diagnostic value of clinical finding and laboratory tests in group A beta hemolithic streptocoxic tonsyllopharyngi̇ti̇s diagnosis

Introduction: In our country, especially in primary care practice, Centor criteria and rapid antigen detection test (RADT) are widely used in the diagnosis of Group A Streptekok tonsillopharyngitis. The aim of the study was to determine the diagnostic value of the signs and symptoms for streptococcal pharyngitis, the effectiveness of the Centor and Modified Centor (McIsaac) criteria, and the sensitivity and selectivity of the Rapid antigen test to recognize GAS tonsillopharyngitis. Materials and Methods: Study Between May 2019, February 2020, it was performed in Aydın Adnan Menderes University Practice and Research Hospital, the policlinics of Family Medicine, Pediatrics and ENT and in child and adult emergency departments. 405 patients older than 36 months who were admitted to the study with complaints of sore throat or other acute tonsillopharyngitis lasting at least one day were included. Two throat swab samples were collected from each patient, one for RADT and one for throat culture, and blood samples for infection values. After the data were collected, statistical analysis was done through SPSS package program. The necessary ethics committee permissions of the study were obtained from Adnan Menderes University Medical Faculty Non-Interventional Clinical Research Ethics Committee. Results: The mean age of 405 patients who participated in the study was 24.7 ± 16.4 (3-81 years). The majority of women (53.6%; n = 217) and those who applied to the emergency service (60.7%; n = 246) were. GAS positivity in culture was 7.9% and rapid antigen test positivity was 9.9%. GAS positivity was 2.0% in patients with Centor score of 0-1: 12,1% in 2-3 and 45.8% in 4. The GAS positivity was 0.4% in patients with McIsaac score of 0-1: 11.6% in those with 2-3 and 35.7% in patients with 4-5. The sensitivity of the rapid antigen test was 75.8%, and its selectivity was 95.6% (PPV 59.5% in prevalence 7.9% and NPV 97.9%). Rapid antigen test results were consistent with culture results in all patients and in all Centor categories. According to the Centor categories, RADT sensitivity varied between 33.3-90.9% and selectivity between 71.4-99.2%. Conclusion: Our study results regarding the diagnostic power of Centor and McIsaac criteria and validity of rapid antigen test in the diagnosis of Group A Streptococcal tonsillopharyngitis are similar to the original Centor study and other study results in the literature. Considering that acute tonsillopharyngitis cases are evaluated using the Centor predictive model and rapid antigen test, studies in our country on primary family practice should be done on GAS positivity and the diagnostic power of RADT and clinical prediction systems.