Testing for malignant hyperthermia (MH) susceptibility is usually performed either in relatives of MH susceptible persons or in patients with an MH suspicious clinical event. There are two diagnostic options: muscle biopsy with in-vitro contracture testing and molecular genetic diagnosis. Patients with familial MH mutations are usually tested genetically. A genetic screening can be performed in clinical events with a high pretest probability. MH susceptibility can be confirmed by presence of a diagnostic MH mutation. Absence of MH mutations cannot exclude MH. The only option to exclude MH susceptibility is contracture testing.