Haptoglobin Unit Converter
Haptoglobin Unit Converter
Convert haptoglobin between mg/dL, g/L and mg/L, with the adult reference interval and what a low value means in haemolysis.
Haptoglobin converter
Mass unitsHaptoglobin 95 mg/dL
Formula and conversion factor
mg/L = mg/dL × 10
- molar units
- not used — haptoglobin circulates as polymers of 86 to 900 kDa depending on Hp1/Hp2 phenotype, so no single molecular weight applies
Worked example
Haptoglobin 95 mg/dL
95 ÷ 100 = 0.95 g/L
95 mg/dL = 950 mg/L
Interpretation in suspected haemolysis
| Test | Intravascular haemolysis | Extravascular haemolysis |
|---|---|---|
| Haptoglobin | Very low or undetectable | Low or normal |
| LDH | Markedly raised | Raised |
| Unconjugated bilirubin | Raised | Raised |
| Reticulocytes | Raised | Raised |
| Plasma free haemoglobin | Raised | Normal |
What haptoglobin measures
Haptoglobin binds free haemoglobin released from lysed red cells, and the complex is cleared rapidly by hepatic macrophages through the CD163 receptor. Because clearance of the complex is far faster than synthesis of new haptoglobin, even modest intravascular haemolysis drives the plasma level down, often to undetectable. That consumption is what makes it one of the most sensitive markers of haemolysis available.
The interpretation has two important limits. Haptoglobin is a positive acute-phase reactant, so infection, inflammation, malignancy and corticosteroids all raise it — an inflamed patient who is haemolysing may show a haptoglobin in the normal range. Conversely, chronic liver disease reduces synthesis and lowers it without any haemolysis, and around 1% of people of African ancestry have congenital anhaptoglobinaemia and no measurable haptoglobin at all.
For these reasons haptoglobin is read alongside LDH, unconjugated bilirubin and the reticulocyte count. The combination of an undetectable haptoglobin with a raised LDH is far more informative than either result alone.
Frequently asked questions
How do I convert haptoglobin from mg/dL to g/L?
Divide by 100. A haptoglobin of 95 mg/dL is 0.95 g/L. Some laboratories report mg/L, which is the mg/dL value multiplied by 10.
Why is there no µmol/L conversion for haptoglobin?
Haptoglobin circulates as polymers whose size depends on the Hp1/Hp2 phenotype, ranging from about 86 to 900 kDa. There is no single molecular weight, so a molar conversion would be arbitrary.
Can haptoglobin be normal in haemolysis?
Yes. It is an acute-phase reactant, so concurrent infection or inflammation can raise it into the normal range despite ongoing haemolysis. Interpret with LDH, bilirubin and reticulocytes.
What lowers haptoglobin apart from haemolysis?
Chronic liver disease reduces synthesis, and congenital anhaptoglobinaemia — present in roughly 1% of people of African ancestry — means none is produced at all.
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References
- Barcellini W, Fattizzo B. Clinical applications of hemolytic markers. Dis Markers. 2015.
- Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, haptoglobin.