Cryohemolysis for the detection of hereditary spherocytosis: correlation studies with osmotic fragility and autohemolysis.
Laboratory methods aimed to assess the presence of spheroidal cells such as osmotic fragility, autohemolysis, and glycerol lysis time are very elaborate, time consuming, and often give inconclusive results. We have developed a diagnostic test based on a unique sensitivity of HS cells to hypertonic cryohemolysis and analyzed blood samples of 55 HS patients. The patients were divided into two subgroups, clinically affected probands and their relatives. To get quantitative comparisons with the classic methods, the cryohemolysis results were compared to two parameters of the osmotic fragility test: the salt concentration that causes 50% hemolysis, and the percent lysis at a constant salt concentration. Autohemolysis results were also compared. To evaluate which of these tests has the best analytical power, we calculated the mean results and 2 SDs of each parameter in a control group, and then looked to see which of them was best in identifying the patients. The cryohemolysis test was the single parameter that identified all cases including asymptomatic carriers of the disease. The ability of this test to identify the less severe cases probably reflects the dependency of the cryohemolysis on factors that are more related to the primary membrane molecular defects and less by the surface area to volume ratio.
Streichman
S
S
Department of Hematology, Rambam Medical Center, Haifa, Israel.
Gescheidt
Y
Y
D005069:Evaluation Studies as Topic; D005615:Freezing; D006461:Hemolysis; D006801:Humans; D008722:Methods; D009996:Osmotic Fragility; D013103:Spherocytosis, Hereditary / Q000175:diagnosis*