Insulin Assay Standardization: Leading to Measures of Insulin Sensitivity and Secretion for Practical Clinical Care

In their recent commentary, Staten et al. (1) describe their very valuable attempt to standardize insulin assays. Their aim is to allow quantitative comparison of the results obtained in one lab with those measured by a different assay in another lab. I'd like to highlight an issue when it comes to reporting the results. The insulin concentration must be stated in SI units nowadays, i.e., in pmol/l instead of μU/ml. The latter unit refers to the biologic action of this hormone (i.e., its blood glucose–lowering activity) and the former to the number of insulin molecules in a given volume. A fixed conversion factor is used to convert the microunits …