[Changes in serum vitamin D assay usage and the need for evidence-based recommendations].

Result of renewed interest due to the large amount of literature that reported numerous epidemiological data demonstrating the high prevalence of vitamin D deficiency, the number of prescriptions of serum vitamin D assays has grown exponentially in recent years with a cost for health insurance that increased almost fivefold in four years. The quantitative and qualitative analysis of assays carried out from 2007 to 2011 in a French university adult short-stay hospital shows changes in practices not only quantitatively but also qualitatively resulting in an overtime increase in the frequency of prescriptions in patients younger, less vitamin D deficient and more frequently male. In the absence of French guidelines, this development cannot be qualified as deviant but justifies the urgent need to establish evidence-based recommendations for good prescriptions and adequate assays of blood vitamin D.