Lactate increase and oxygen desaturation in mitochondrial disorders – Evaluation of two diagnostic screening protocols

Background: Mitochondrial disorders are characterized by an accumulation of lactate and an insufficient oxygen extraction from blood during exercise. Therefore, both parameters (lactate and oxygen saturation) can be used as screening tests in mitochondrial disorders. However, conflicting results regarding sensitivities and specifities of both tests have been reported. Method: We examined 27 patients with genetically defined mitochondrial disorders (single deletions n=15, multiple deletions n=5, A3243G mutation n=7), patients with other neuromuscular disorders, and healthy controls. In the first protocol subjects…