milligram per decilitre
One milligram in one decilitre — a tenth of a litre — so 1 mg/dL is 10 mg/L. It is the unit of clinical chemistry in the United States, and the one blood glucose, cholesterol and creatinine are reported in there.
Watch out: Most of the world reports the same measurements in millimoles per litre, and that conversion needs the molar mass of the specific analyte — it is not a property of the unit and this site will not perform it silently. Blood glucose at 100 mg/dL is 5.55 mmol/L; the same 100 mg/dL of cholesterol is 2.59 mmol/L. Different substances, different factors, and no unit picker can bridge them without being told which one you mean.
| 1 | 10 |
The decilitre survives in medicine and almost nowhere else. It comes from an era when clinical assays were run on 100 mL of sample, and the unit stayed after the volumes shrank because a century of reference ranges and clinical judgement were written against it.
About the milligram per decilitre
The decilitre is a hundred millilitres, and it persists in clinical chemistry for the same reason inches persist in plumbing: an enormous body of accumulated judgement is expressed in it. Every reference range an American physician learned, every treatment threshold in an older guideline, and every patient who knows their own numbers knows them in mg/dL.
The relationship to the rest of this type is a clean factor of ten — 1 mg/dL = 10 mg/L — and that factor of ten is precisely the trap. A result carried between a clinical report and an environmental or laboratory system without conversion is out by an order of magnitude in a direction that looks plausible either way.
The conversion people actually want is to mmol/L, and it is not available here on purpose. Millimoles count particles and milligrams weigh them, so the bridge is the molar mass of the specific substance: glucose at 180.16 g/mol gives the familiar divide-by-18, and cholesterol at 386.7 g/mol gives divide-by-38.7. A unit picker offering "mg/dL → mmol/L" would have to assume a substance, and assuming wrong is a factor of two on a number someone may act on.
One milligram per decilitre in every mass concentration unit
| 10 | milligram per litre (mg/L) | |
| 10,000 | microgram per litre (µg/L) | |
| 0.01 | gram per litre (g/L) | |
| 10 | microgram per millilitre (µg/mL) | |
| 1 | milligram per decilitre (mg/dL)this unit | |
| 0.001 | gram per decilitre (g/dL) | |
| 0.01 | kilogram per cubic metre (kg/m³) | |
| 10,000 | nanogram per millilitre (ng/mL) |