Indicate !Hemolysis

• Drastic decrease: intravascular
  • Hemolytic anemias (autoimmune, microangiopathic, transfusion reaction)
  • G6PD deficiency or sickle cell crisis (if there’s intravascular spillover)
  • Mechanical hemolysis (prosthetic heart valves, ECMO)
• Slight decrease: extravascular

Also low in:

• Severe liver disease (reduced production)
• DIC or massive transfusion (consumption)
• Genetic haptoglobin deficiency (rare, benign)