Creatinine, 24 Hour Urine

Test Code

381

CPT Codes
82570

Includes

CPT code 81050 may be added at an additional charge for volume measurement

Preferred Specimen

10 mL of a 24-hour urine collection (unpreserved) collected in a plastic leak-proof container

Minimum Volume

2 mL

Other Acceptable Specimens

Acidified urine collected in Urinalysis Transport Tube (yellow-top, blue fill line, preservative) tube

Instructions

Please indicate the total urine volume and the time of collection on the request form.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days

Methodology
Colorimetric (C) • Kinetic

Setup Schedule

Set up: Daily; Report available: 1-3 days

Reference Range

<3 Years	Not established
3-8 Years	0.10-0.80 g/24 h
9-12 Years	0.20-1.40 g/24 h
13-17 Years	0.40-1.90 g/24 h
>17 Years	0.50-2.15 g/24 h

Clinical Significance

Creatinine is the endproduct of creatine metabolism. Creatine is present primarily in muscle and the amount of creatinine produced is related to total skeletal muscle mass. Daily creatinine production is fairly constant except when there is massive injury to muscle. The kidneys excrete creatinine very efficiently and blood levels and daily urinary excretion of creatinine fluctuates very little in healthy normal people. Since blood and daily urine excretion of creatinine shows minimal fluctuation, creatinine excretion is useful in determining whether 24-hour urine specimens for other analytes (e.g., protein) have been completely and accurately collected.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.