Intervention to reduce inappropriate ionized calcium ordering practices: a quality-improvement project

The importance of an abnormal ionized calcium (iCa) measurement in noncritically ill patients is unclear. Furthermore, iCa monitoring is more expensive than measurement of total calcium and consumes more laboratory resources. We hypothesize that most iCa tests are ordered for routine monitoring in asymptomatic patients, and results do not influence clinical management.

To characterize and to intervene on iCa test-ordering practices among our institution's hospital-based internal medicine clinicians.

A quality-improvement project, with retrospective review of clinical records. We retrospectively identified the first 100 consecutive patients admitted to our hospital internal medicine (HIM) services during January 2012 with an iCa test ordered during their hospitalization. We reviewed clinical records to determine the appropriateness of iCa test ordering and of the ordering department. An educational intervention regarding the appropriateness of iCa testing was undertaken targeting HIM clinicians.

The effect of the intervention was assessed by identifying a sample of the first 100 consecutive patients admitted to HIM services during November 2012 and by comparing the proportion of iCa tests ordered by HIM clinicians before and after the intervention.

HIM services were responsible for 38% of iCa measurements before the educational intervention, with the remainder originating primarily from the Emergency Department (29%) and intensive care units (28%). After the intervention, the internal medicine services were responsible for 13% of iCa measurements, which represented a 66% reduction (p = 0.0007).

A simple intervention based on clinician education can reduce the frequency of routine iCa monitoring in stable hospitalized patients.