Glycerol lysis time as a screening test for erythrocyte disorders.

Abstract

Abstract A rapid, simple procedure, measuring the rate of hemolysis of erythrocytes suspended in glycerol, was used to screen blood samples for erythrocyte abnormalities. The normal range was determined by measuring the time required for hemolysis of 50 per cent of the erythrocytes (GLT 50 ) in a standardized glycerol mixture. In 70 normal subjects the median GLT 50 value was 42 seconds, with a skewed distribution and a range of 26 to 72 seconds. A population of 484 hospitalized patients had a median GLT 50 value of 39 seconds and a clinical range (95 per cent confidence interval) of 26 to 73 seconds. Species differences in glycerol permeability have been attributed in the past to differences in the erythrocyte membrane lipids. In this study, abnormally slow hemolysis was found not only in disorders of erythrocyte lipids, but also in other conditions, particularly hemoglobinopathies. The GLT 50 value was elevated in 40 out of 41 cases of β-thalassemia trait. Microcytic erythrocytes (MCV ⩽ 75 μ 3 ) could often be distinguished on the basis of GLT 50 values: thalassemia trait > 100 seconds (35 out of 41 cases), iron deficiency anemia ⩽ 100 seconds (19 out of 21 cases), and chronic renal disease ⩽ 73 seconds (20 out of 22 cases). Abnormally rapid hemolysis was found in some cases of hereditary spherocytosis. This procedure may be applicable to mass screening for selected erythrocyte disorders and may also be useful for monitoring the effects of membrane-active agents.