Recent Changes

Hemoglobin: The new conversion factor we use is 0.1551, instead of 0.6205. The new factor gives the conversion of hemoglobin tetramer mass concentration into SI unit (mmol/l). The molecular weight of the hemoglobin tetramer, including the heme groups, is 64,458 g/mol (approximately 4 x 16,000). With a normal hemoglobin concentration of 15 g/dl, the concentration in mmol/l is 2.327. Thus, the conversion factor yields 0.1551 given by 2.327 divided by 15. Note that 4 x 0.1551 is 0.6205, the conversion factor to convert g/dl into the concentration of hemoglobin monomers, not tetramers.

Glycated hemoglobin (HbA1c): According to the consensus statement on the worldwide standardization of HbA1c measurement, HbA1c should be indicated as mmol/mol. Main reason: use of the SI unit should remove potential confusion between HbA1c values as a percentage and blood glucose values in mmol/l. The SI Unit Converter includes the "former" conversion factor of 0.01. We have included a new page for conversion to the new SI Unit here.

Insulin: We changed the conversion factor of insulin from 6.945 to 6.0. Different insulin assays may have caused discrepancies in the past, but biological activities of insulin batches do not alter anymore, and 6.0 is the relevant factor today. Further reading: Heinemann L. Insulin Assay Standardization: Leading to Measures of Insulin Sensitivity and Secretion for Practical Clinical Care.