Lactic Acid: Pyruvic Acid Ratio Blood Test - NOT CURRENTLY AVAILABLE

What is the purpose of this test?

Order this Lactic Acid: Pyruvic Acid (L/P) Ratio Blood Test to evaluate the likelihood of several disorders related to mitochondrial metabolism. A common symptom of most mitochondrial metabolism disorders is lactate acidosis; thus, this L/P ratio test may also help determine the causes of lactic acidosis.

The mitochondria, the cell's powerhouse, metabolize glucose to produce ATP, the energy used by the body to perform necessary functions. For mitochondrial metabolism, one of the steps requires pyruvic acid, and the following step requires oxygen. Pyruvic acid (pyruvate) is a substance produced in cells and used to make energy. When the oxygen level is low, pyruvate gathers and is converted to lactic acid (lactate), resulting in a build-up of lactate and lactic acidosis. An alternative cause is mitochondrial dysfunction, when the oxygen pathway is blocked, resulting in increased pyruvate and, consequently, more lactate. Therefore, the L/P ratio will be elevated in these cases.

Yet, there are also rare congenital disorders (inborn errors of metabolism) in which pyruvate is not converted to lactate. One example is pyruvate dehydrogenase deficiency. In these cases, pyruvate will accumulate, the blood level will be high, and the lactate to pyruvate ratio will be low.

When should I order an L/P Ratio Blood Test?

Individuals may order this L/P Ratio Blood Test if they have experienced symptoms associated with a mitochondrial metabolism disorder. Common signs or symptoms of a mitochondrial metabolism disorder include the following:

• Muscle weakness 
• Exercise intolerance
• Impaired hearing and vision
• Ataxia
• Seizures 
• Learning disabilities 
• Heart defects
• Diabetes
• Poor growth