Overuse Ordering Serum Vitamin B12: A Call for Appropriate Ordering Guidelines Based on a Single Institutional Experience.

Objective: Vitamin B12 is an essential nutrient for numerous functions in the human body. As such, many clinical scenarios justify assaying serum B12; however, there are no evidence-based guidelines available for determining when to order B12 tests. Here we investigate B12 assay ordering patterns to identify methods of enhancing efficiency and minimizing inappropriate requests.

Methods: All serum B12 requests within the year spanning July 2018 to June 2019 were reviewed using the hospital's health information system. These amounted to 3,400 requests, of which data from the first 1,000 were evaluated. Patient demographics, hematological data, serum folate, and ferritin were extracted from the electronic requests. Physician identity and request reason were retrieved where available.

Results: Of the 877 B12 requests for which patient age was available, the majority (80.3%) were for young and middle-aged patients. Interestingly, serum B12 was low in only a quarter of the 1,000 reviewed requests; the remaining three quarters had normal levels. Folate, which can be ordered with vitamin B12, was tested in 82 cases, of which only two (2.4%) had folate deficiency.

Conclusion: This study highlights a high occurrence of improper ordering of vitamin B12 assays, indicating a need for revised guidelines to promote optimal test ordering.