Amino Acids (Plasma)

Plasma

1 mL

0.5 mL

Sterile screw capped vial

Collect 1-4 milliliters of blood in sodium heparin (green top) tube. Although not required, sample collection after a 3-4 hour fast is optimal. Draw off plasma. Store frozen at –20°Celsius. Preferred volume: 1.0 milliliter, minimum volume: 0.5 milliliter

Freeze as soon as possible after collection; Ship within 24 hours. Ship samples priority overnight on 3-4 lbs of dry ice. Sample must arrive in our lab Monday - Saturday. We do NOT accept Sunday or holiday deliveries.

Room Temperature: Not stable; Refrigerated: not stable; Frozen: indefinitely @ -20C; Freeze/Thaw: None

Incorrect sample type received; Sample received thawed; Sample hemolyzed or bloody

Plasma amino acid (MET02) is a quantitative assay that is fundamental to the investigation of several inherited metabolic diseases.

Amino acids are the basic structural units that comprise proteins and are found throughout the body. Many inborn errors of amino acid metabolism, including phenylketonuria and tyrosinemia, have been identified. Amino acid disorders can manifest at any age, but most become evident in infancy or early childhood. These disorders result in the accumulation or the deficiency of 1 or more amino acids in biological fluids which leads to the clinical signs and symptoms of the particular amino acid disorder. Disorders that can be diagnosed by Plasma Amino Acids (MET02) include, but are not limited to, phenylketonuria, tyrosinemia, citrullinemia, non-ketotic hyperglycinemia, maple syrup urine disease, and homocystinuria. The assay is also key for the continued monitoring of treatment plans for these disorders and useful for assessing nutritional status of patients. The clinical presentation is dependent upon the specific amino acid disorder. In general, affected patients may experience failure to thrive, neurologic symptoms, digestive problems, dermatologic findings, and physical and cognitive delays. If not diagnosed and treated promptly, amino acid disorders can result in intellectual disability and death. Treatment for amino acid disorders includes very specific dietary modifications. Nonessential amino acids are synthesized by the body, while essential amino acids are not and must be obtained through an individual's diet. Therapeutic diets are coordinated and closely monitored by a dietician and/or physician. They are structured to provide the necessary balance of amino acids with particular attention to essential amino acids and those which accumulate in a particular disorder. Patients must pay close attention to the protein content in their diet and generally need to supplement with medical formulas and foods. Dietary compliance is monitored by periodic analysis of plasma amino acids. In addition, plasma amino acid analysis may have clinical importance in the evaluation of several acquired conditions including endocrine disorders, liver diseases, muscle diseases, neoplastic diseases, neurological disorders, nutritional disturbances, renal failure, and burns.

Plasma Amino Acid Testing (MET02) may also be used for assessment of Variants of Uncertain Significance (VUS) identified during genetic testing (e.g. Next Generation Sequencing or Capillary Sequencing Testing).

This assay is performed by LabCorp in its Burlington, NC laboratory. It is not eligible for STAT testing.

Liquid chromatography/tandem mass spectrometry (LC/MS-MS)