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Test Code LAB749 Urea Clearance, Plasma or Serum and Urine

Important Note

If a serum or plasma BUN result is not available within 72 hours of the urine collection or a patient's height and weight is not provided to complete the calculation,  the clearance will be cancelled and a 24 hr Urea Nitrogen will be ordered.  

Reporting Title

Urea Clearance

Methodology

Roche Diagnostics,  RMH, GMC and MH 

Performing Laboratory

OhioHealth Laboratory Services-RMH, GMC and MH Core Laboratories

Specimen Requirements

Plasma or serum and urine are required for this test. Plasma or serum must be drawn within 72 hours of urine collection and submitted along with urine specimen. 72 hours (the day before the collection, the day of the collection, or the day after the collection.)

 

Urine

5 mL from a 24-hour urine collection in a screw-capped, plastic urine container. No preservative. Mix well before taking 5-mL aliquot. Refrigerate specimen during collection, and send specimen refrigerated.

Note:  1. Patient’s height and weight, starting and ending times of collection, and 24-hour volume are required on request form for processing.

2. Follow instructions in “Urine Collection” in “Special Instructions.”

3. Label specimen appropriately (urine).

 

Submit only 1 of the following specimens:

 

Preferred:

Serum

Draw blood in a gold-top top serum gel tube(s). Spin down and send 1 mL of serum refrigerated.
Note:

1. A speckled-top serum gel tube (s) or a plain, red-top tube(s) is also acceptable.

2. For inpatients, laboratory will coordinate draw upon receipt of 24-hour urine specimen.

3. Patient’s height and weight are required on request form for processing.

4. Indicate serum on request form.

5. Label specimen appropriately (serum).

6. Sample stability: 7 days

 

Alternate: 

Plasma

Draw blood in a mint green-top (heparin) gel tube(s). Spin down and send 1 mL of heparinized plasma refrigerated.

Note:  1. For inpatients, laboratory will coordinate draw upon receipt of 24-hour urine specimen.

2. Patient’s height and weight are required on request form for processing.

3. Indicate plasma on request form.

4. Label specimen appropriately (plasma).

Specimen Transport Temperature

Refrigerate OK/Ambient OK/Frozen OK

Reference Values

40-100 mL/min

Day(s) Test Set Up

Monday through Sunday; Continuously

Test Classification and CPT Coding

84545

Special Instructions