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Test ID URCU Uric Acid, 24 Hour, Urine

Reporting Name

Uric Acid, U

Useful For

Assessment and management of patients with kidney stones, particularly uric acid stones

Specimen Type


Necessary Information

24-Hour volume is required.

Specimen Required

Container/Tube: Plastic, 5-mL tube (T465)

Specimen Volume: 5 mL

Collection Instructions:

1. Add 10 g of boric acid as preservative at start of collection.

2. Collect urine for 24 hours.

3. Mix well before taking 5-mL aliquot.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values

>  or = 16 years: Diet-dependent: <750 mg/24 hours

Reference values have not been established for patients who are less than 16 years of age.


The reference value is for a 24-hour collection. Specimens collected for other than a 24-hour time period are reported in unit of mg/dL for which reference values are not established.

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
URCU Uric Acid, U 3087-4


Result ID Test Result Name Result LOINC Value
UACID Uric Acid, U 3087-4
TM29 Collection Duration 13362-9
VL27 Urine Volume 3167-4
UACN1 Uric Acid Concentration 21587-1

Clinical Information

Uric acid is the end-product of purine metabolism. It is freely filtered by the glomeruli and most is reabsorbed by the tubules. There is also active tubular secretion.


Increased levels of uric acid in the urine usually accompany increased plasma uric acid levels unless there is a decreased excretion of uric acid by the kidneys. Urine uric acid levels reflect the amount of dietary purines and also endogenous nucleic acid breakdown.


Urinary uric acid excretion is elevated in a significant proportion of patients with uric acid stones.


Uric acid excretion can be either decreased or increased in response to a variety of pharmacologic agents.


Urine uric acid levels are elevated in states of uric acid overproduction such as in leukemia and polycythemia and after intake of food rich in nucleoproteins.

Clinical Reference

Newman DJ, Price CP: Renal function and nitrogen metabolites. In Textbook of Clinical Chemistry. Edited by NW Tietz. Philadelphia, WB Saunders Company, 1999, pp 1245-1250

Analytic Time

Same day/1 day

Method Name


Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.







50% Acetic Acid


Boric Acid


Diazolidinyl Urea


6M Hydrochloric Acid


6M Nitric Acid


Sodium Carbonate








If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.