Detection of malignant hyperthermia susceptibility using a spin label technique on red blood cells.

Using spin labelled red blood cells and electron paramagnetic resonance spectroscopy (EPR), we observed that halothane 3 mmol litre-1 produced a much greater decrease in the rotational correlation time of red blood cells from individuals who were at risk for malignant hyperthermia (MH), compared with normals. Subsequently we performed blind tests on 14 individuals whose MH susceptibility status had been determined on the basis of in vitro contracture studies. When compared with the results of the in vitro contracture studies, the EPR studies predicted correctly the patients' status in 13 of the 14 individuals.