Osmotic fragility - red cell
Last updated: Friday, 30, April, 2004
This test is probably obsolete and is rarely ordered.
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5 mL blood in lithium heparin, or defibrinated blood.
Susceptibility to osmotic lysis is tested using fresh blood or blood incubated at 37°C for 24 hours.
Median corpuscular fragility (MCF) is the saline concentration causing 50% lysis.
| Reference Interval|
MCF 4.0-4.45 g/L (68-81 mmol/L) NaCl in fresh samples.
4.65-5.9 g/L (79-100 mmol/L) in incubated samples.
The test is rarely used in the investigation of haemolytic anaemia; confirms the presence of spherocytes.
Abnormal results are found in a number of hereditary haemolytic anaemias; results are not diagnostic.
Dacie JV. The Haemolytic Anaemias. 3rd ed. Churchill Livingstone 1985.