Duplicate laboratory orders: a College of American Pathologists Q-Probes study of thyrotropin requests in 502...

To examine the frequency and cause of duplicate thyrotropin (TSH) testing.

Five hundred two institutions, ranging in size from fewer than 100 to more than 600 beds, examined consecutively processed TSH assays to identify duplicate orders. Duplicates were defined as two or more TSH tests performed within 7 days. All together, participants submitted data on 221,476 TSH orders.

The median institution reported that 1.5% of TSH tests duplicated a TSH order that had been received from the same patient within the previous 7 days. Ten percent of institutions reported that 4.5% or more of their TSH tests were duplicates. Institutions with higher duplicate rates tended to be larger (ie, they had a greater number of occupied beds) and to have duplicate tests that were more likely to be ordered by a physician other than the one who ordered the initial test. Participants reported that for 19% of duplicate orders, physicians were unaware that the first test had been ordered. Physicians also indicated that duplicate assays were ordered to see if a previous result had changed (15%) or to check on the accuracy of a previous result (13%). Participants reported that 11% of duplicate TSH assays that their laboratory performed had apparently never been ordered.

A large number of institutions are performing duplicate TSH tests that, in most cases, appear to be medically unnecessary. Institutions aiming to reduce the frequency of duplicate testing should consider policies that decrease the opportunity for different physicians to order tests on a single patient and should increase the accuracy with which physician orders are transmitted to the laboratory.