Blood glucose measurement units

The international standard way of measuring blood glucose levels are in terms of a molar concentration, measured in mmol/L (millimoles per litre; or millimolar, abbreviated mM). In the United States, mass concentration is measured in mg/dL (milligrams per decilitre).

Since the molecular weight of glucose C6H12O6 is about 180 g/mol, for the measurement of glucose, the difference between the two scales is a factor of 18, so that 1 mmol/L of glucose is equivalent to 18 mg/dL.