The in vitro contracture test (IVCT) based on European Malignant Hyperpyrexia Group criteria including the linked quality guarantee is carried out in 6 centres in Germany. Due to the genetic heterogeneity of malignant hyperthermia. This test remains the existing standard, despite intensive search for less invasive diagnostic methods. The test is necessary for clarification of narcosis incidents and diagnosis of individual disposition of MH-afflicted families. The analysis of 11 years of experience with 1.001 investigations in the Leipzig centre focuses on characteristic problems. It indicates, that severe courses with resulting fatality (37 cases in the whole observation period in the centre district had a decreasing tendency. Independently thereof the rate of demands for diagnostics remains constant at 125 per year. Apparently MH related incidents are under better control now. Of the requested diagnostics 85% are related to anaesthesia incidents, 15% to other MH related problems [myopathies, unexplained fever attacks]. Of the patients tested 59.7% were MH-negative (MHN), 33.7% MH-positive (MHS) and 6.3% were equivocally positive (MHE). A parallel part of the study regarding IVCT and histology/morphometry in 230 consecutive examinations did not show any correlation. Ultrastructural investigations accordingly are carried out only if there is suspicion of myopathy. Differentiation of the in vitro threshold values shows a relation to the patients' risks. Low threshold values were detected in persons diagnosed as MHS from families with MH related deaths: one man diagnosed MHS died from an anaesthesia-unrelated MH crisis. In a parallel test of MH-positive muscles with new inhalational narcotics (sevoflurane, desflurane), a strong correlation to triggering of contracture by halothane was detected. In contrast, no information about a false negative result exists at this time. MH manifestation was observed postoperatively only in one patient 1337 patients MHS, 63 MHE). However, in 3 cases cardio-circulatory arrests occurred under local anaesthesia without further consequences. The analysis documents the safety of IVCT and the clarity of its results. IVCT is the base for an improved communication with patients and colleagues.