Inpatient Test Utilization and Test Volume Benchmarking: A Q-Probes Study

Test-ordering practices vary widely between and within health care organizations, and methods used to benchmark test utilization data are unstandardized.

To develop and apply standardized methodology to compare inpatient test utilization data submitted by laboratories enrolled in a College of American Pathologists Q-Probes study.

Participating laboratories provided inpatient test volumes for 50 designated analytes and total inpatient days for 2019 or a recent 12-month period. Test utilization patterns were characterized by studying test volumes standardized per 1000 inpatient days. Test volume variability used the standardized median absolute deviation; standardized test volumes were evaluated by calculating comparative ranges for each analyte. Standardized test volumes falling outside their respective comparative ranges are referred to as outliers in this study. Volume data were tested for association with stewardship practices and institutional demographics.

Methodology using standardized test volume data identified test groups that are commonly used in the inpatient setting and efficiently identified volume outliers. High test volume outliers included creatine kinase myocardial band, free prostate-specific antigen, myoglobin, serotonin release assay, and hepatitis B serologies; no low-volume outliers were observed. Among 33 participants, 13 (39%) had no test volume outliers, while 5 (15%) showed multiple tests (13-34) with comparatively high volumes. No statistically significant relationships were found between stewardship practices and test-ordering patterns.

Our approach can be used to measure inpatient test volume data across organizations and for identifying test volumes falling outside of the standardized comparative ranges that may require interventions to change test utilization practices.