Iron studies and transferrin, a source of test ordering confusion highly amenable to clinical decision support

An important cause of laboratory test misordering and overutilization is clinician confusion between tests with similar sounding names or similar indications. We identified an area of test ordering confusion with iron studies that involves total iron binding capacity (TIBC), transferrin, and transferrin saturation. We observed concurrent ordering of direct transferrin along with TIBC at many hospitals within our health system and suspected this was unnecessary.

We extracted patient test results for transferrin, TIBC and other biomarkers. Using these data, we evaluated both patterns of test utilization and test result concordance. We implemented a clinical decision support (CDS) alert to discourage unnecessary orders for direct transferrin.

Using linear regression, we were able to predict transferrin from either TIBC alone or TIBC with other analytes with a high degree of accuracy, demonstrating that in most cases, direct transferrin in combination with TIBC provides little if any additional diagnostic information beyond TIBC alone. The CDS alert proved highly effective in reducing transferrin test utilization at four different hospitals.

Concurrent ordering of direct transferrin and TIBC should usually be avoided. Removal of transferrin or TIBC from the test menu or implementation of CDS may improve utilization of these tests.