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Orotic Acid, Urine

Test Codes

Order as Miscellaneous Send Out, Beaker: XMISC, Mayo: OROT

Department

Send Outs

Instructions

• Because of the importance of sample processing, it is required that the patient submits the sample only to the Beaumont Outpatient Laboratory at the Grosse Pointe, Royal Oak, Troy Hospital campuses.
• Please refer to the Specimen Collection Manual for instructions on 24-Hour or Random Urine Collection:
  • Urine 24-Hour Collection - Inpatient
  • Urine 24-Hour Collection - Outpatient
  • Urine 24-Hour Collection - Outreach
  • Random Urine Collection

Specimen Collection Criteria

Collect (preferred specimen): 24-hour urine sample with no preservative.
Also acceptable: 10 mL random urine specimen in a screw-capped container (preferred) or other sterile collection cup. (Minimum: 3.0 mL)

• Keep 24-hour urine specimen iced or refrigerated during collection.
• Include start and end dates and times for the collection period on the specimen container.
• Critical frozen. Submit the specimen to the Laboratory immediately after the end of collection. The specimen MUST be frozen within 4 hours of collection.

Urine Preservative Options
No Preservative	6N Hydrochloric Acid	Boric Acid (10g)	Sodium Carbonate	50% Acetic Acid
REQUIRED	Unacceptable	Unacceptable	Unacceptable	Unacceptable

Rejection Criteria

Specimens not collected and processed as indicated. 

In-Lab Processing

Critical frozen. Measure total volume of 24-hour urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot 10.0 mL from the well-mixed 24-hour urine collection or random urine and freeze (-20°C/-4°F or below) immediately. (Minimum: 3.0 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 4 hours
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Medical Laboratories, Rochester, MN.

Performed

Varies.
Results available in 4-8 days.

Reference Range

By report.

Test Methodology

Colorimetric.

Interpretation

Orotic acid is an intermediate in pyrimidine biosynthesis.

Increased urinary excretion of orotic acid is observed in inborn errors of the urea cycle, with the exception of deficiency of the first enzymes in the cycle, carbamoyl-phosphate synthetase and N-acetylglutamate synthetase.

When orotic acid is measured after a protein load or allopurinol administration, excretion of orotic acid is a very sensitive indicator or ornithine carbamoyl-transferase activity.

Interpretation must be correlated with clinical and other laboratory findings.

Clinical Utility

This assay aids in the differential diagnosis of hyperammonemia and primary orotic aciduria.

CPT Codes

83921

Contacts

Last Updated

7/21/2024