Cortisol — µg/dL to nmol/L

In short To convert cortisol from µg/dL to nmol/L, multiply by 27.5893 — so one µg/dL is 27.5893 nmol/L, and one nmol/L is 0.0362459 µg/dL. 5 µg/dL is 138 nmol/L; 10 µg/dL is 276 nmol/L; 20 µg/dL is 552 nmol/L. The factor comes from the molar mass, because cortisol has a molar mass of 362.46 g/mol; that is why it differs for every analyte and why a single "lab unit converter" factor does not exist. Cortisol swings enormously through the day — a morning figure and an evening figure from the same healthy person can differ several-fold — so the time the blood was drawn matters more than for almost any other test on this page. Converting the units is the easy part; comparing two results drawn at different hours is not a conversion problem at all. This converts units. It does not interpret results, does not compare your value against a reference interval, and is not a substitute for the clinician who ordered the test — reference intervals differ between laboratories, methods and populations.