Impact of the Introduction of Guidelines on Vitamin B12 Testing

Abstract

To the Editor: In 2008, our laboratory received 42 546 requests for vitamin B12 testing, a 72% increase from 2003. We provide B12 testing to a population of 361 028 (according to the Irish census of 2006), a 6.3% increase from 2002 (1). This change in population cannot explain this substantial increase in B12 testing. This increasing laboratory workload is not unique to B12 testing or to our laboratory (2). We produced local guidelines to advise on appropriate testing for B12. The indications included in the guidelines were: hematologic (unexplained anemia/other cytopenias, unexplained macrocytosis), neurologic (peripheral neuropathy, dementia, unexplained neurology), pregnancy, glossitis, malabsorption, metformin therapy, and dialysis patients. These guidelines were introduced in May 2009. Subsequently, testing for B12 was performed if the clinical details were consistent with the guidelines. If the clinical indication was not consistent with local guidelines, the test was not performed, and the clinician was informed. Additionally, we suggested a minimum retest interval of 6 months, although we did …