Specimen Requirements

Patient Preparation

1. Hydrate the patient by administering a minimum of 600 mL of water.

2. Patient should be without tea, coffee, ascorbic acid, ketone bodies, trimethoprim, cimetidine, quinine, quinidine, procainamide, cefoxitin, cephalothin, phenacetin, levodopa, and thiazides on the day of testing.

3. Exercise may caused increased creatinine clearance.

Specimen Collection
Plasma or serum and urine are required.

Blood specimen should preferably be drawn at the mid-point of the 24-hour period of urine collection but will be accepted if drawn within 24 hours before or after urine collection.

Urine

Submit an entire 24-hour urine collection in a plastic urine container. No preservative. Refrigerate specimen during collection, and send specimen refrigerated.
Note: 1. Be sure to include patient’s height and weight on container. Measured total creatinine and predicted creatinine excretion will be calculated to determine adequacy of urine specimen, as well as corrected versus uncorrected creatinine clearance results.

2. Starting and ending times of collection are required.

3. Follow instructions in Urine Collection in Special Instructions.

Submit only 1 of the following specimens:

Plasma

Container/Tube: Light green-top (lithium heparin) tube

Specimen: 1 mL of lithium heparin plasma

Transport Temperature: Ambient

Collection Instructions:

Note:

1. Indicate plasma.
2. Label specimen appropriately (plasma).

Serum

Container/Tube: Plain, red-top tube or gold serum gel tube

Specimen: 1 mL of serum

Transport Temperature: Ambient

Collection Instructions:

Note:

1. Indicate serum.
2. Label specimen appropriately (serum).