Edit page | Page history | Printable version

Fragility test

a test that measures the resistance of erythrocytes to haemolysis in hypotonic saline solutions; erythrocytes to be tested are added to varying concentrations of saline (usually ranging from 0.85 to 0.10% sodium chloride with 0.05% increments), and beginning and complete haemolysis are measured; normal erythrocytes show initial haemolysis at concentrations of 0.45 to 0.39% and complete haemolysis at 0.33 to 0.30%; in hereditary spherocytosis the fragility of the erythrocytes is markedly increased, whereas in thalassaemia, sickle cell anaemia, and obstructive jaundice the fragility of the erythrocytes is usually reduced.

Synonym: erythrocyte fragility test.