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Order Code OAUS Organic Acids Screen, Urine Spot


Ordering Guidance


The preferred screening test for organic acidemias is OAU / Organic Acids Screen, Random, Urine, which should be ordered unless collecting or sending urine is difficult or not feasible.



Necessary Information


1. Patient's age is required.

2. Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.



Specimen Required


Supplies: Card-Blood Spot Collection (Filter Paper) (T493)

Collection Container:

Preferred: Blood Spot Collection Card

Acceptable: Whatman Protein Saver 903 paper, PerkinElmer 226 filter paper, Munktell filter paper

Specimen Volume: 1 Filter paper card soaked with urine, typically requires 2 to 3 mL of urine

Collection Instructions

1. Soak a filter paper card with urine, approximately 22 cm(2) in area (typically requires 2 to 3 mL of urine; exact measurement is not important as urine volume will be normalized to creatinine).

Note: Filter paper sample may be collected by dipping the card into a collection cup of urine. Avoid dilute urine if possible.

2. Let urine dry on filter paper at ambient temperature in a horizontal position for a minimum of 3 hours.

3. Do not expose specimen to heat or direct sunlight.

4. Do not stack wet specimens.

5. Keep specimen dry.


Useful For

Diagnosis of inborn errors of metabolism using dried urine specimens

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

Organic Acids Scrn, US

Specimen Type

Urine

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 28 days FILTER PAPER
  Ambient  14 days FILTER PAPER
  Refrigerated  14 days FILTER PAPER

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

An interpretive report will be provided.

Method Description

Urine collected on filter paper is reconstituted in water and a volume corresponding to 0.25 mg of creatinine is acidified and then extracted with ethyl acetate. After separation and evaporation of the solvent phase, the dry residue is sialylated and analyzed by capillary gas chromatography mass spectrometry. When indicated, oximation of 2-keto acids is performed by reaction with hydroxylamine hydrate.(Sweetman L. Organic acid analysis. In: Hommes FA, ed. Techniques in Diagnostic Human Biochemical Genetics. Wiley-Liss; 1991:143-176; Hoffman GF, Feyh P. Organic acid analysis. In: Blau N, Duran M, Blaskovics ME, Gibson KM, eds. Physician's Guide to the Laboratory Diagnosis of Metabolic Diseases. Springer; 2003:27-44; Cowan T, Pasquali M. Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1143)

Day(s) Performed

Monday through Saturday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

83919

Forms

1. Biochemical Genetics Patient Information (T602)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.