Blood count and blood group
Haptoglobine
A protein that clears released hemoglobin; a low value may fit faster breakdown of red blood cells.
Everything about this testWhat it measures
Haptoglobin is a protein made by the liver. When red blood cells break down in the bloodstream, hemoglobin (the red pigment) is released. Haptoglobin binds this hemoglobin and carries it to the liver, where both are broken down. If many red blood cells break down (hemolysis), haptoglobin is used up and the value falls. Haptoglobin is also an acute phase protein: during inflammation the liver makes more of it.
- Faster breakdown of red blood cells in the bloodstream (hemolysis), as an addition to tests for anemia
- An inflammatory reaction in the body, as a side effect
High
A raised value is usually due to inflammation or infection, because haptoglobin then rises like other acute phase proteins. Corticosteroids (such as prednisone) can also raise the value. A raised value on its own is not considered meaningful. However, inflammation can mask a fall caused by hemolysis, so that the value then looks normal.
Low
A low value means haptoglobin is being used up faster than it is made. This fits faster breakdown of red blood cells, for example due to an inherited abnormality of the red blood cells, an artificial heart valve, immune reactions against your own red blood cells or certain medicines. A low value can also be due to reduced production in severe liver disease, or after major blood loss. Hemolysis often goes with symptoms of anemia, such as tiredness and shortness of breath, sometimes with yellow skin or dark urine. Some people naturally have a low value without anything being wrong.
If your result is abnormal
With a low value, the GP looks at hemoglobin, reticulocytes, LDH and bilirubin to see whether there really is hemolysis. If the picture fits hemolysis, referral to an internist (specialist in internal medicine) usually follows to look for the cause.
Reliability
Haptoglobin is sensitive to breakdown of red blood cells in the bloodstream, but says nothing about the cause. The value is therefore assessed together with hemoglobin, reticulocytes (young red blood cells), LDH and bilirubin. A normal value does not fully rule out hemolysis, because inflammation can raise the value at the same time. According to the Dutch Society for Clinical Chemistry (NVKC), the test is not often requested, because the cause of anemia is usually found with other tests.
Limitations
- Inflammation, infection and corticosteroids raise the value and can hide a fall caused by hemolysis.
- Severe liver disease lowers the value through reduced production, even without hemolysis.
- In a small number of people the value is naturally low or unmeasurable due to an inherited variant, without causing symptoms.
- In newborns the value is normally low.
How common is this
Anemia is common, especially in women and older people. Anemia caused by faster breakdown of red blood cells is a small part of this; the cause is usually a shortage of iron, vitamin B12 or folic acid, or a chronic disease.
Who is this useful for
Useful with anemia where breakdown of red blood cells may be the cause, for example with a raised reticulocyte count or a raised LDH or bilirubin. Also useful with a known inherited abnormality of the red blood cells or an artificial heart valve. In people without anemia and without symptoms, a single value says little.
Downsides and risks
- A low value without anemia can cause unnecessary worry and unnecessary further tests, while the cause is often a harmless inherited variant.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results