Diagnostic yield of the lactate stress test in 160 patients with suspectedrespiratory chain disorder

Aim of the present study was to investigate the diagnostic yield of the lac tate-stress-test in unselected patients with suspected respiratory-chain di sorder (RCD). Serum lactate was determined before, during and after a IS-mi nute, constant 30W workload on a bicycle in 48 controls and 160 patients wi th suspected RCD. 122 had definite RCD, 38 neurological disorders other tha n RCD. The sensitivity, specificity, positive predictive value, negative pr edictive value and pre-test likelihood of the test was 69, 74, 89. 42 and 7 6 % respectively. In conclusion, the lactate-stress-test proved a powerful tool to assess impaired oxidative metabolism in RCDs.