CPT® Code 82131

The CPT® Code 82131 refers to a laboratory test that quantitatively measures the presence of a single amino acid in a specimen, which can be either blood or urine. Amino acids are essential organic compounds that serve as the building blocks of proteins and play a critical role in various metabolic processes within the body. This test is particularly relevant for individuals suspected of having an inborn error of metabolism, a group of genetic disorders that disrupt normal metabolic pathways. The clinical manifestations of these disorders often present in infancy or early childhood and can vary significantly based on the specific amino acid involved. Symptoms may include feeding difficulties, poor growth or failure to thrive, seizures, muscle weakness, renal or liver dysfunction, developmental delays, and cognitive impairments. To perform this test, a blood sample is typically collected through venipuncture, which is a procedure that involves puncturing a vein to obtain blood. Alternatively, a urine sample can be collected either through a voided specimen or catheterization. The analysis of the serum, plasma, or urine is conducted using advanced techniques such as liquid chromatography-tandem mass spectrometry, which allows for precise measurement of amino acid concentrations. The quantitative assessment of amino acids is crucial for monitoring treatment and dietary adherence in patients with specific metabolic disorders, including phenylketonuria (PKU), cystinuria, and Hartnup disease. In these cases, the test results can guide clinical decisions and help manage the patient's condition effectively.