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Test ID URAU Urea, 24 Hour, Urine

Useful For

Assessment of protein intake and/or nitrogen balance

Method Name

Kinetic UV Assay 

Reporting Name

Urea, U

Specimen Type

Urine

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

Specimen Volume: 4 mL

Collection Instructions:

1. Add 10 g of boric acid as preservative at start of collection. (If boric acid is not available, refrigerate specimen during collection.)

2. Collect urine for 24 hours.

3. Mix well before taking aliquot.

Additional Information:

1. 24-Hour volume is required.

2. See Urine Preservatives in Special Instructions for multiple collections.

 

Urine Preservative Collection Options

Ambient:

No

Refrigerated:

Yes

Frozen:

Yes

6N HCl:

Yes

50% Acetic Acid:

Yes

Na2CO3:

Yes

Toluene:

Yes

6N HNO3:

Yes

Boric Acid:

Preferred

Thymol:

Yes

Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Clinical Information

Urea is a low molecular weight substance (Mol. Wt.=60) that is freely filtered by glomeruli and the majority is excreted into the urine, although variable amounts are reabsorbed along the nephron. It is the major end product of protein metabolism in humans and other mammals. Approximately 50% of urinary solute excretion and 90% to 95% of total nitrogen excretion is composed of urea under normal conditions. Factors which tend to increase urea excretion include increases in glomerular filtration rate, increased dietary protein intake, protein catabolic conditions, and water diuretic states. Factors which reduce urea excretion include low protein intake and conditions which result in low urine output (eg, dehydration).

Reference Values

10-35 g/24 hours

Cautions

No significant cautionary statements

Day(s) Performed

Monday through Sunday; Continuously  

Report Available

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

84540

NY State Approved

Yes