Identification of susceptibility to malignant hyperpyrexia.

While the serum level of creatine phosphokinase is useful as a screening test for malignant hyperpyrexia it does not provide certain identification of susceptible individuals. A much more accurate prediction may be made by pharmacological testing in vitro of muscle biopsy specimens. Individuals susceptible to malignant hyperpyrexia have muscle with heightened sensitivity to halothane, caffeine, succinylcholine, potassium chloride, and temperature change. Use of this test allows separation of susceptible individuals from those not at risk in families of patients who have experienced malignant hyperpyrexia.