Validation of Procedural Codes to Identify Infants Evaluated for Serious Bacterial Infection

To validate a novel coding method using Current Procedural Terminology, Fourth Edition (CPT-4) codes for identifying infants who underwent a full evaluation for serious bacterial infection (SBI).

We performed a multicenter, retrospective examination to determine the accuracy of a combination of CPT-4 codes for blood, cerebrospinal fluid (CSF), and urine cultures to identify previously healthy infants ≤90 days old admitted to a general care floor and fully evaluated for SBI. Full SBI evaluation was defined as blood, CSF, and urine cultures performed during the emergency department encounter or corresponding hospitalization. Cases were defined as infants who had codes for blood, CSF, and urine cultures (87040, 87070, and either 87086 or 87088), and these were compared with all other encounters. We validated these findings by comparing medical record documentation of blood, CSF, and urine cultures to the corresponding CPT-4 codes, with calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

We identified 8548 qualifying encounters, and 347 (4%) had a combination of CPT-4 codes 87040, 87070, and either 87086 or 87088. This combination had a sensitivity of 100% (95% confidence interval, 98.9-100) and specificity of 98.2% (95% confidence interval, 97.3-98.8) for identifying infants who underwent full SBI evaluation for an unknown source.

CPT-4 codes provide an accurate means to identify infants who underwent complete SBI evaluation.