Evaluating the modified Centor criteria as a screening tool before polymerase chain reaction testing and antibiotic...

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.

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.

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.

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.