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Lactate stress testing in 155 patients with mitochondriopathy
Josef Finsterer1, Erika Milvay
1Ludwig Boltzmann Institute for Research in Neuromuscular Disorders, Vienna, Austria.
Summary
The lactate stress test (LST) effectively detects mitochondriopathy (MCP) with 67% sensitivity and 94% specificity. This simple test aids in assessing impaired oxidative metabolism in MCP patients.
Area of Science:
- Biochemistry
- Neurology
- Metabolic Disorders
Background:
- Mitochondriopathy (MCP) is a group of disorders affecting mitochondrial function.
- Limited data exist on the diagnostic utility of the lactate stress test (LST) in large MCP cohorts.
Purpose of the Study:
- To evaluate the diagnostic yield of the LST in patients with suspected or confirmed MCP.
- To determine the sensitivity and specificity of LST in identifying impaired oxidative metabolism.
Main Methods:
- Serum lactate levels were measured in 155 MCP patients, 62 controls, and 31 non-MCP neurological disorder patients.
- Measurements were taken at rest, during a 15-minute bicycle exercise (30W), and post-exercise.
- The LST was considered abnormal if more than two of five lactate values exceeded established cut-off levels.
Main Results:
- The LST demonstrated a sensitivity of 67% and a specificity of 94% for detecting MCP.
- Among patients with abnormal LST results, 62% had normal resting lactate levels.
- The test identified impaired oxidative metabolism in a significant number of MCP patients.
Conclusions:
- The LST is a sensitive and specific tool for diagnosing mitochondriopathy (MCP).
- It is a simple yet powerful method for assessing impaired oxidative metabolism in MCP.
- The LST is valuable even when resting lactate levels are normal.