General Information:
Lactate is a byproduct of cellular metabolism, derived from lactic acid. It is produced during anaerobic glucose metabolism (glycolysis), primarily in skeletal muscles, the brain, and red blood cells. Lactate formation occurs when oxygen supply to tissues is insufficient, and energy production shifts to less efficient anaerobic pathways.
During glycolysis, pyruvate is converted to lactate by the enzyme lactate dehydrogenase (LDH) when mitochondria cannot process pyruvate efficiently. Lactate levels correlate with fatigue during physical activity and can indicate oxygen delivery issues or metabolic imbalances in pathological conditions.
- Sample Type: Venous blood.
- Fasting for 12 hours before the test is required.
- Avoid physical and emotional stress 30 minutes before the test.
- Refrain from smoking 30 minutes prior to the test.
- Avoid applying a tourniquet during blood collection.
- Minimize hand and wrist activity before the test.
- Assessment of oxygen delivery in shock or circulatory disturbances.
- Evaluation of acidosis causes, including metabolic acidosis.
- Monitoring tissue perfusion and oxygen transport.
- Sports physiology and medical research.
- Differential diagnosis of myopathies and neonatal enzymopathies.
- Asphyxia in newborns.
- Type 2 diabetes.
- Symptoms of oxygen deficiency or acid-base imbalance (e.g., nausea, excessive sweating, rapid breathing).
- Suspected sepsis, shock, myocardial infarction, cardiac failure, or renal failure.
- Diagnosis of inherited metabolic or mitochondrial disorders.
Interpretation of Lactate Levels:
Elevated lactate levels (lactic acidosis) are classified into two types based on the mechanism of formation:
Type A Lactic Acidosis (Oxygen Deficiency):
- Shock (trauma or massive blood loss).
- Sepsis.
- Acute cardiovascular conditions.
- Congestive heart failure.
- Severe pulmonary diseases or respiratory failure.
- Pulmonary edema.
- Severe anemia.
Type B Lactic Acidosis (Metabolic or Increased Demand):
- Liver diseases.
- Kidney diseases.
- Diabetes mellitus.
- Leukemia.
- AIDS.
- Glycogen storage diseases (e.g., glucose-6-phosphatase deficiency).
- Drug and toxin effects (e.g., salicylates, cyanides, metformin, methanol).
- Inherited metabolic and mitochondrial disorders (e.g., ATP synthesis-related muscular dystrophies).
- Physical exertion or seizures.
Other Causes of Elevated Lactate Levels:
- Alcoholism or chronic alcohol abuse.
- Acute bleeding or congestive heart failure.
- Cirrhosis or severe liver diseases.
- Pregnancy (third trimester).
- Severe vascular conditions.
- Bacterial endocarditis.
- Polymyelitis.
- Hyperventilation.
- Insulin injection or glucagon effect.
- Vitamin B1 deficiency.
- Reye syndrome.
Medications or Substances Affecting Lactate Levels:
- Aspirin overdose.
- Excessive adrenaline, ethanol, or fructose.
- Drugs like metformin, glucocorticoids, and certain antibiotics (e.g., nalidixic acid).
Decreased Lactate Levels:
- Anemia.
- Significant weight loss.
- Interference from substances like methylene blue or morphine.
Clinical Implications:
Monitoring lactate levels helps evaluate tissue oxygenation, diagnose metabolic or mitochondrial disorders, and guide treatment in critical conditions like sepsis, shock, or acidosis. Early intervention based on lactate levels can improve outcomes in acute and chronic diseases.