Amino Acid Analysis

 Biochemical Genetics Laboratory Amino Acid Analysis

INDICATIONS FOR TESTING:
Amino acid analysis of serum is indicated in infants presenting with acidosis with an anion gap, seizures, lethargy, developmental delay, hyperammonemia or failure to thrive. Analysis of urine is indicated when a renal transport defect is suspected.

METHODOLOGY:
Analysis is performed by Ion Exchange Chromatography with post column ninhydrin detection. Two wavelengths are monitored to insure accurate evaluation of secondary amino acids and to check for purity. Creatinine is used in the expression of urine values. Quantitation of amino acids is achieved by integrating the area of each peak and comparison to an internal standard. Calibration is routinely performed with reference materials. Retention times are used for identification. Amino acid analysis can be ordered as a screen or a quantitation. Both requests are analyzed in the same way. With a screen only an interpretation of the results is reported. With a quantitation, both values and an interpretation are reported. Quantitation of individual amino acids may also be requested.

TURN-AROUND TIME:
Amino Acid analysis is completed within a time of 3 working days following specimen receipt. Samples are analyzed daily. One-day turn-around time is offered on acutely ill infants with a strong suspicion of a metabolic disorder.

SPECIMEN REQUIREMENTS:

  • Serum or Plasma: 1.0 mL
  • Urine: 2.0 mL
  • CSF: 1.0 mL

Collection Notes:

  • Urine: A 24-hour collection is preferred but random collections are accepted.
  • Do not use preservatives (especially strong acids).

Shipping and Handling:

  • Optimal: Ship frozen with dry ice in an insulated container
  • Acceptable: Ship thawed with cool pack in an insulated container

Use overnight delivery if available.

CPT CODE:

  • Amino Acid Screen: 82128
  • Amino Acid Quantitative: 82131
  • Amino Acid Individual: 82131

FOR MORE INFORMATION, PLEASE CONTACT:
Phone:
(727) 767-8689 (Laboratory)
Fax: (727) 767-8514
E-mail: sbenfor1@jhmi.edu