Summary of laboratory tests to confirm haemolysis
| Test | Finding in haemolysis | Cause |
|---|---|---|
| Reticulocyte count | Raised | Bone marrow response to anaemia can lead to macrocytosis |
| Lactate dehydrogenase | Raised | Released from the breakdown of red blood cells |
| Unconjugated bilirubin | Raised | Increased haemoglobin breakdown |
| Haptoglobin | Decreased | Binds to free haemoglobin |
| Direct antiglobulin test | Positive in immune cases of haemolytic anaemia | Detects immunoglobulins or complement bound in vivo to red cell membranes |
| Blood film | May show abnormal red blood cells | Morphology dependent on the cause of haemolysis |
| Urinalysis for haemoglobinuria | A positive urine dipstick for blood, but microscopy negative of red blood cells | Occurs in severe acute intravascular haemolytic anaemia that exhausts haptoglobin-binding capacity; free haemoglobin is filtered by the glomerulus and haemoglobinuria occurs |