Specimen Collection Manual and Test Catalog

1 mL of serum or plasma, minimum 0.2 mL; AND 10 mL aliquot of 24-hour urine, minimum 2 mL

Collect urine in 24-hour urine collection container, either with 6N HCl added or with no preservative added. Mix well. Estimate total collection volume from 24-hour urine container. Remove required aliquot. Record total volume on both aliquot tube and request slip (if applicable).

Lithium heparin plasma is acceptable from in-house collection.

Provide patient height and weight on lab request (centimeters and kilograms). Serum or plasma should be collected within 24 hours of collection of the 24-hour urine specimen.

Allow serum to clot. Centrifuge to separate serum or plasma within 2 hours of collection.

Refrigerated.

See individual member listing.

A complete 24-hour urine collection is required. Other specimens will be rejected.

Creatinine clearance: Male 85-125 mL/min; female: 75-115 mL/min
Urine creatinine: Male: 1-2 gm/24 hours; female 0.8-1.8 gm/24 hours
Serum creatinine: 0.7-1.5 mg/dL. Age and sex dependent.

Creatinine clearance creatinine - 24-hour urine creatinine - serum 24-hour total volume

CREATININE CLEARANCE, URINE, CLRB

Creatinine clearance is used to evaluate the glomerular filtration rate (GFR). Clearance is defined as that volume of plasma from which a measured amount of substance could be completely eliminated into the urine per unit of time. Daily creatinine production is fairly constant when there is massive injury to muscle.