All form of hemolysis can lead to

• sudden decrease in Hct
• slight incraease in MCV (because reticulocytes are larger than normal cells)
• Increased LDH, indirect bilirubin (chronic process --> gall stones), and reticulocytes
• decreased haptoglobin
• hyperkalemia
• Folate deficiency
• Urine test for hemosiderin: may be positive
• Urine test for hemoglobin: may be positive
• Red cell survival time with Cr51: shortened

Causes of Haemolysis

In intravascular haemolysis free haemoglobin is released which binds to haptoglobin. As haptoglobin becomes saturated haemoglobin binds to albumin forming methaemalbumin (detected by Schumm's test). Free haemoglobin is excreted in the urine as haemoglobinuria, haemosiderinuria

• *>> high LDH, (indirect) bilirubin, and reticulocytes count with a normal MCV, low haptoglobin and hemoglobinuria

Intravascular haemolysis: causes

• mismatched blood transfusion
• IV RhoD immune globulin infusion
• G6PD deficiency*
• MAHA - red cell fragmentation: heart valves, TTP, DIC, HUS
• paroxysmal nocturnal haemoglobinuria