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Test ID URCON Urea, Random, Urine

Ordering Guidance

A timed 24-hour urine collection is the preferred specimen for measuring and interpreting this urinary analyte. See URCR / Uric Acid, 24 Hour, Urine.


Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children.

Specimen Required

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Container/Tube: Plastic tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Useful For

Assessment of kidney failure (prerenal vs acute kidney injury)

Method Name

Kinetic Ultraviolet Assay

Reporting Name

Urea, Random, U

Specimen Type


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  30 days
  Ambient  7 days

Reference Values

No established reference values


Random urine urea may be interpreted in conjunction with serum urea, using both values to calculate fractional excretion of urea.


The calculation for fractional excretion (FE) of urea is

FE(U)= ([U(urine)XCreat(serum)]/[U(serum)XCreat(urine)]) X 100

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US 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


LOINC Code Information

Test ID Test Order Name Order LOINC Value
URCON Urea, Random, U 3092-4


Result ID Test Result Name Result LOINC Value
URCON Urea, Random, U 3092-4

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day to 24 days


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