Bilirubin (Total) Unit Converter
Bilirubin (Total) Unit Converter
Convert total bilirubin between mg/dL, µmol/L, mg/L and µg/dL, with adult reference ranges and jaundice thresholds.
Bilirubin (Total) converter
Mass ⇄ molarTotal bilirubin 1.4 mg/dL
Formula and conversion factor
mg/dL = µmol/L ÷ 17.104
- 17.104
- derived from the molecular weight of bilirubin IXα, 584.66 Da
- mg/L
- mg/dL × 10
- 17.1
- the rounded factor used in most published tables
Worked example
Total bilirubin 1.4 mg/dL
1.4 × 17.104 = 23.9 µmol/L
= 14.0 mg/L = 1400 µg/dL
Reference ranges and thresholds
| mg/dL | µmol/L | |
|---|---|---|
| Adult reference interval | 0.1 – 1.2 | 2 – 21 |
| Gilbert syndrome, typical | 1.2 – 3.0 | 21 – 51 |
| Clinically visible jaundice | > 2.5 – 3.0 | > 43 – 51 |
| Child-Pugh 2 points | 2 – 3 | 34 – 51 |
| Child-Pugh 3 points | > 3 | > 51 |
What bilirubin measures
Bilirubin is the end product of haem catabolism. It is produced in macrophages, carried to the liver bound to albumin, conjugated with glucuronic acid by UGT1A1, and excreted in bile. A rise can therefore reflect a problem at any of three points: too much production, impaired conjugation, or obstructed excretion.
Fractionation into conjugated and unconjugated is what makes the number interpretable, and it should be the automatic next step for any raised total. A predominantly unconjugated rise points to haemolysis, ineffective erythropoiesis, resorption of a large haematoma, or reduced conjugation — most often Gilbert syndrome, which affects several per cent of the population and is entirely benign. A predominantly conjugated rise points to hepatocellular disease or biliary obstruction and always requires investigation.
Bilirubin also appears as a component in most hepatic prognostic scores, including Child-Pugh, MELD in all its versions, ALBI and the Maddrey discriminant function. In those it functions less as a marker of jaundice than as a measure of the liver’s excretory reserve.
Frequently asked questions
How do I convert bilirubin from mg/dL to µmol/L?
Multiply by 17.1. A bilirubin of 1.4 mg/dL is 23.9 µmol/L. Divide by 17.1 to go the other way.
At what level does jaundice become visible?
Around 2.5 to 3 mg/dL, or 43 to 51 µmol/L. It appears in the sclerae before the skin because scleral elastin binds bilirubin avidly.
What is a normal total bilirubin?
Roughly 0.1 to 1.2 mg/dL, or 2 to 21 µmol/L in adults. Gilbert syndrome typically produces an isolated unconjugated bilirubin of 1.2 to 3 mg/dL with otherwise normal liver tests.
Why does my bilirubin rise when I am unwell or fasting?
In Gilbert syndrome, fasting, intercurrent illness, dehydration and exertion all reduce UGT1A1 activity and raise unconjugated bilirubin transiently. It is benign and needs no treatment.
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References
- Kwo PY, Cohen SM, Lim JK. ACG Clinical Guideline: evaluation of abnormal liver chemistries. Am J Gastroenterol. 2017;112(1):18–35.
- PubChem CID 5280352 — bilirubin, molecular weight 584.66.