Is It Time to Remove Total Calcium from the Basic and Comprehensive Metabolic Panels? Assessing the Effects of American Medical Association-Approved Chemical Test Panels on Laboratory Utilization.

Background: The necessity of individual tests within the most commonly used disease-oriented test panels has not been well established. We evaluated test-ordering practices for total calcium, both before and after implementation of American Medical Association (AMA)-approved panels (basic metabolic panel [BMP] and comprehensive metabolic panel [CMP]) in our electronic ordering system.

Methods: We performed a retrospective review of all total calcium orders placed during April and June 2018, before and after implementation of the panels. Orders from inpatient, outpatient, and emergency department (ED) care units were totaled, and the percentage of abnormal test results was calculated. We then queried institutional databases to determine the number of unique patients with calcium-related diagnoses and compared the rates from a 5-month period both before and after implementation of the panels.

Results: Total test volumes and tests per unique patient increased by more than 3-fold after implementation of calcium-containing AMA-approved panels, with the majority of those orders coming from BMPs and CMPs. The rate of low calcium values increased because of the shift toward more inpatient testing; however, the percentage of abnormal results within each patient population (inpatient, outpatient, ED) decreased. The prevalence of hypo- and hypercalcemia-related diagnoses among patients in the 5 months after implementation did not change significantly (1.29% before implementation vs 1.27% after implementation).

Conclusions: Implementation of BMPs and CMPs dramatically increased total calcium testing volumes without changing the rate of calcium-related diagnoses. The results suggest that the increase in total calcium orders associated with panel-based testing largely constitutes excess or unnecessary testing.