When haptoglobin levels are decreased, along with an increased reticulocyte count and usually also a decreased RBC, haemoglobin and haematocrit, then it is likely that the patient has some degree of haemolytic anaemia.
If the haptoglobin is normal and the reticulocyte count is increased, then RBC destruction may be occurring in organs such as the spleen and liver. Because the freed haemoglobin is not released into the bloodstream, the haptoglobin is not used up and so is normal.
If the haptoglobin concentrations are normal and the reticulocyte count is not increased, then it is likely that any anaemia present is not due to RBC breakdown.
If haptoglobin levels are decreased without any signs of haemolytic anaemia, then it is possible that the liver is not producing adequate amounts of haptoglobin.
Haptoglobin is considered an “acute-phase” protein; this means that it will be elevated in many inflammatory diseases, such as , acute rheumatic disease, heart attack, and severe infection. This will complicate the interpretation of the haptoglobin results. Haptoglobin testing is not generally used to help diagnose or monitor these conditions.
Haptoglobin levels may be affected by massive blood loss and by conditions associated with kidney dysfunction.
Drugs that can increase haptoglobin levels include androgens and corticosteroids. Drugs that can decrease haptoglobin concentrations include isoniazid, quinidine, streptomycin, and birth control pills.