Erythrocyte fragility screening is not a tool for diagnosis of human malignant hyperthermia.

ABSTRACT

The fragility of erythrocytes from 21 patients undergoing in vitro skeletal muscle contracture testing for malignant hyperthermia (MH) susceptibility was examined. Osmotic fragility was determined by the degree of hemolysis in buffered saline solutions of decreasing osmotic strength. Halothane-induced fragility was determined in an isotonic solution containing increasing percentages of halothane saturated solution. The effects of six different incubation conditions prior to performing fragility tests were examined in an attempt to optimize discrimination of MH susceptible patients, including the following 1) no preincubation; 2) 24-hr incubation at 4 degrees C; 3) 72-hr incubation at 4 degrees C; 4) 24-hr incubation at 37 degrees C; 5) 24-hr incubation at 22 degrees C with plasma from an MH-susceptible patient; and 6) 24-hr incubation at 22 degrees C with plasma from a normal patient. Despite examining six different incubating conditions and the two methods of hemolysis induction, no differences in erythrocyte fragility were detected between patients diagnosed as MH susceptible or normal. Erythrocyte fragility testing is not useful for diagnosing MH susceptibility.