Test Background Red blood cells with membrane defects that occur in hereditary spherocytosis are more susceptible to lysis when subjected to severe cold. Increased levels of haemolysis can also be found in stomatocytosis.
Clinical Indications Suspected hereditary spherocytosis Suspected stomatocytosis
Reference Range Normal range <2 % A result of >8 % is diagnostic of hereditary spherocytosis
Sample Required 4 mL EDTA (lavender top) adults 0.5 mL EDTA (lavender top) paediatrics
Sample Volume 0.5 mL adult tube 0.2 mL paediatric tube
Turnaround Time 24 hours
Notes Samples must be tested within 24 hours of collection