Creatinine, Urine

Cassandra Greaves C, Test

NEW YORK DOH APPROVED: YES

CPT Code: 82570
Order Code: C170

F2-Isoprostane/Creatinine: C261

Microalbumin/Creatinine: C919

AspirinWorks/Creatinine: C922

ABN Requirement: No
Specimen: Random Preservative-free Urine
Volume:  10.0 mL
Minimum Volume:  0.5 mL
Container: Yellow Top Urine tube

Collection:

  1. Collect urine sample according to standard protocols.
  2. Transfer aliquot from a clean urine cup into a Yellow Top tube using the vacutainer transfer device included with the Yellow Top tube.
  3. Gently invert tube 5 times.
  4. Label sample according to standard protocols.

Transport: Store specimen at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.

Stability:

Ambient (15-25°C): 7 days
Refrigerated (2-8°C):
14 days
Frozen (-20°C):
6 months

Causes for Rejection: Specimens other than preservative-free urine; improper labeling; samples not stored properly; samples older than stability limits

Methodology: Photometric

Turn Around Time:  1 to 3 days

Reference Range:

AgeRange (mg/dL)
≤6 Months2-28
7-11 Months2-31
1-2 Years2-110
3-8 Years2-130
9-12 Years2-160
>12 Years, Male20-320
>12 Years, Female20-275

Clinical Significance: Creatinine is the end product 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.

Limitations: Calcium dobesilate, levodopa and α-methyldopa cause artificially low creatinine results. High homogentisic acid concentrations in urine samples lead to false results. Acetaminophen, Acetylcysteine, and Metamizole are metabolized quickly. Therefore, interference from these substances is unlikely but cannot be excluded.

The CPT codes provided 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 payer being billed.