Modified end-point glycerol hemolysis assay as a screening test for hereditary spherocytosis that requires no venipuncture.

The high specificity of the "pink test" for the detection of hereditary spherocytosis has been confirmed. A modification of the test is proposed that requires only 10 microliter of blood taken without anticoagulant (a "direct pink test"), thus eliminating the necessity of venipuncture, especially cumbersome in newborns and infants.