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Test Code LAB4209 UREA CLEARANCE

Important Note

No BUN collection will be requested for patients that have had a BUN result in the past two days

Specimen Type

24-hour urine collection

Collection Instructions

Collect a 24-hour urine in a 24-hour dark plastic urine container. Refrigerate during collection. Collect serum at the same time as urine collection if there are no BUN results in the last two days

Specimen Volume

50 mL urine

Minimum Volume

1 mL urine

Turnaround Time

STAT: 1 hour
Routine: 4 hour

Test Schedule

Daily

Sample Stability

Room Temp: 2 days
Refrigerated: 7days
Frozen: 1 month

Specimen Processing

Invert 24 hour urine container several times to mix the specimen.
Aliquot 50 mL of a well-mixed 24-hour urine collection into a leakproof plastic urine container.
Aliquot 5 mL into a transparent red top tube.
Record collection time and total volume.
Freeze 50ml Specimen Aliquot.

Method

Colorimetric and calculation

Reference Ranges

BUN 7-23 mg/dL

Urea, Urine 12-20 g/24h

Urea Clearance mL/min/1.73m2

Test Components

BUN, mg/dL;

Urea, Urine, g/24 hours;

Urea Clearance, mL/min/1.73 m2.

CPT Codes

84545

Rejection Criteria

Plasma with anticoagulants containing ammonium ions.