Emergency severity index triage system correlation with emergency department evaluation and management billing codes and total professional charges.

Objectives: All services provided by physicians to patients during an emergency department (ED) visit, including procedures and "cognitive work," are described by common procedural terminology (CPT) codes that are translated by coders into total professional (physician) charges for the visit. These charges do not include the technical (facility) charges. The objectives of this study were to characterize associations between Emergency Severity Index (ESI) acuity level, ED Evaluation and Management (E&M) billing codes 99281-99285 and 99291, and total ED provider charges (sum of total procedure and E&M professional charges). Secondary objectives were to identify factors that might affect these associations and to evaluate the performance of ESI and identified variables to predict E&M code and average total professional charges.

Methods: The authors reviewed 276,824 patient records for calendar year 2007, of which 193,952 adult ED visits from three different ED types (community, university-based academic, and non-university-based academic) met inclusion criteria. Correlations between 1) ESI level and E&M billing code per visit by institution and 2) ESI and total professional charges were analyzed using Spearman rank correlation. Linear regression analysis was performed to identify variables that significantly affected these correlations.

Results: ESI level and E&M codes were moderately correlated (Spearman r = 0.51). ESI levels corresponded proportionately to higher E&M codes. ESI 1, 2, and 3 most frequently corresponded with E&M level 5 (50, 62, and 45%, respectively), and ESI 4 and 5 most frequently corresponded with E&M level 3 (56 and 67%, respectively). Only age by decade significantly affected the association between ESI level and E&M billing code. The mean total professional charge for all patient encounters was $421 (SD ± $204) with increasing mean charges per patient by increasing ESI acuity. Race and E&M code significantly affected the relationship between ESI level and total ED professional charges per patient (adjusted r(2) = 0.66).

Conclusions: A moderate, nonlinear correlation exists between ESI acuity levels and ED E&M billing codes. Increasing age affects this correlation. Race and E&M code affect the correlation between ESI level and total professional charges. As such, basic triage data can be used to estimate E&M code and total professional charges. Future studies are needed to validate these findings across other institutional settings.