Evaluating the modified Centor criteria as a screening tool before polymerase chain reaction testing and antibiotic use for group A Streptococcus pharyngitis in a VA population

OBJECTIVES: The modified Centor criteria (MCC) also known as the McIsaac criteria is a screening tool for patients suspicious for group A Streptococcal (GAS) pharyngitis. This study aimed to evaluate the utility of the screening tool and its impact on rapid molecular assay testing for GAS and the prescription of antibiotics. METHODS: Outpatient records of 263 adult patients who received rapid molecular assay testing (Xpert Xpress Strep A polymerase chain reaction [PCR] test) for suspicion of GAS pharyngitis from March 2021 to November 2022 at the Fargo Veteran's Affairs Health Care System were collected by medical record review. RESULTS: MCC scores were calculated for all patients based on symptoms documented in the chart. The majority of patients (54.8%) had a score of 1 or less, and only 6% of encounters had a clinician calculated MCC score documented in the medical record. When the results of the Strep A PCR test were analyzed in relation to the calculated MCC score, the utility of the MCC score was low (low sensitivity and positive predictive value). Despite a negative or canceled PCR test, 14.8% of patients received antibiotics, and antibiotics were often (39.3%) prescribed before the PCR results being available. CONCLUSIONS: MCC scores are an unreliable predictor of positive Strep A PCR tests. Education on the appropriate use of Strep A PCR testing and antibiotics should be emphasized to clinicians.