Creatinine

Cleveland HeartLab C, Test

NEW YORK DOH APPROVED: YES
CPT Code: Serum- 82565, Urine- 82570
Order Code:

Serum– C108
Urine-Panel Codes: C918, C919, C922

ABN Requirement:  No
Synonyms: Creat; Cre; Blood creatinine; Serum Creatinine; Urine Creatinine
Specimen: Serum, Preservative-free Urine
Volume: Serum and Urine: 0.5 mL
Minimum Volume: 0.2mL
Container:

Serum: Gel-barrier tube (SST, Tiger Top)
Urine: Yellow Top tube

Collection: Serum:

  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge at 1300 rcf for 10 minutes.

Urine:

  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 serum or urine at 2°C to 8°C after collection and ship the same day per packaging instructions provided with the Cleveland HeartLab, Inc. shipping box.

Stability: Serum

Ambient (15-25°C): 7 days
Refrigerated (2-8°C): 7 days
Frozen (-20°C): 3 months
Deep Frozen (-70°C): 3 months

Stability: Urine

Ambient (15-25°C): 2 days
Refrigerated (2-8°C): 6 days
Frozen (-20°C): 6 months
Deep Frozen (-70°C): 6 months

Causes for Rejection: Specimens other than serum or 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:

Male
mg/dL
Female
mg/dL
Serum 0.72-1.30 0.55-1.00
Urine 20-300 20-300


Critical Values:

 Test Age Critical Value
mg/dL
Creatinine, Serum All Ages >7.4

Use: Creatinine testing is useful to monitor kidney function in individuals with conditions that affect kidney function, such as diabetes or hypertension, in individuals with kidney disease, or in individuals >65 years of age. Urine creatinine is also commonly used as a reference for other excreted analytes.

Limitations:

Serum: Rifampicin, levodopa, and calcium dobesilate cause artificially low creatinine results. N-ethylglycine ate therapeutic concentrations and DL-proline at concentrations ≥ 1 mmol/L gives false high results. Hemolyzed samples that contain HbF values ≥ 600 mg/dL interfere with the test. Phenindione (2-Phenyl-1, 3-indandione) at therapeutic concentrations interferes with the assay. In very rare cases gammopathy may cause unreliable results. Estimation of the glomerular filtration rate (GFR) on the basis of the Schwartz formula can lead to an overestimation.

Acetaminophen use can falsely decrease test results.

Urine:
Calcium dobesilate, levodopa and α-methyldopa cause artificially low creatinine results. High homogentisic acid concentrations in uric samples lead to false results. Acetaminophen use can falsely decrease test results.