Organic Acid Analysis


Biochemical Genetics Laboratory Organic Acid Analysis

INDICATIONS FOR TESTING:
Organic acid analysis of urine is indicated in infants presenting with acidosis with an anion gap, seizures, lethargy, developmental delay and failure to thrive. Combined with a serum amino acid screen, these tests provide a comprehensive screen for disorders of intermediate metabolism.

METHODOLOGY:
Analysis is performed by Gas Chromatography and Mass Spectrometry (GC/MS). Samples are converted to oxime derivatives prior to extraction by organic solvent. The dried extract is derivatized with trimethylsilyl (TMS) reagent. The TMS derivatives are separated by capillary gas chromatography and detected by Electron Ionization Mass Spectrometry. All significant components are checked against reference libraries for positive identification. Relative amounts are compared to an internal standard. This is a screening method and accurate quantitation of the organic acids with this method is not reliable. The overall pattern is evaluated and compared with patterns obtained from patients with verified inborn errors of metabolism and normal controls.

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

SPECIMEN REQUIREMENTS:

Urine:

  • Preferred Volume = 5.0 mL
  • Absolute minimum = 2.0 mL

Collection Notes:

  • A 24-hour collection is preferred but random collections are accepted.
  • Avoid using soaps when using collection bags.
  • 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 CODES:

  • Organic Acid Screen: 83919

FOR MORE INFORMATION, PLEASE CONTACT:
Phone:
(727) 767-8689 (Laboratory)
Fax: (727) 767-8514
E-mail: benfords@allkids.org