Indications for cobalamin level assessment in departments of internal medicine: a prospective practice survey.

BACKGROUND: Cobalamin (Cb) blood levels are frequently measured among inpatients, but the relevance of Cb determination has not been correctly assessed in this clinical setting.
PURPOSE: We aimed to prospectively evaluate current indications compared to traditional guidelines for assessing Cb blood levels among inpatients from internal medicine departments. STUDY
DESIGN: This study was conducted in French departments of internal medicine between 2008 and 2009. Inpatients who underwent Cb blood level determination during a 6-week study period were eligible.
RESULTS: 380 consecutive adult patients were included. The three most common indications for Cb assessment were anaemia (62.6%), cognitive impairment (20.2%) and undernutrition (17.4%). Traditional indications (ie, macrocytic non-regenerative anaemia, isolated macrocytosis, dementia and proprioceptive disorders) accounted for only 33.9% of all tests. Cb deficiency was identified in 40 (10.5%) of the 380 patients tested. Overall, traditional indications were not associated with a significantly higher prevalence of patients with low Cb levels than current guidelines (14% vs 8.8%; p=0.119). Non-regenerative macrocytic anaemia was the only indication with a significantly better performance compared to all other indications (11 of 62 patients (17.7%) vs 29 of 318 patients (9.1%); OR 2.15 (1.01-4.57), p=0.047). The main aetiological causes of Cb deficiency were intake deficiency, pernicious anaemia and food-Cb malabsorption. Homocysteine or methylmalonic acid dosage testing was very rarely performed.
CONCLUSIONS: Traditional indications did not perform better than other indications observed in current practice for identifying low Cb levels among inpatients from internal medicine departments. Future studies are needed to establish robust guidelines for inpatient screening.