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Test Code CR Creatinine

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Li-Heparin Mint Green Top

Other Acceptable specimens: Serum/Gold Top, Serum/Red Top, Plasma/Lavendar K2 Top

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent room temperature at 15-25oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.

Reference Values

 

Test

Age

Sex

Reference Range
Creatinine 0 - <1 year ALL 0.17 - 0.42 mg/dL
Creatinine 1 - <5 years ALL 0.19 - 0.49 mg/dL
Creatinine 5 - <10 years ALL 0.26 - 0.61 mg/dL
Creatinine 10 - <15 years ALL 0.35 - 0.86 mg/dL
Creatinine 15 - <18 years Male 0.44 - 1.10 mg/dL
Female 0.44 - 1.04 mg/dL
Creatinine >18 years ALL 0.50 - 1.40 mg/dL

 

Note: Creatinine reference range based on in-house studies, recommendations from Tietz Textbook of Clinical Chemistry, and Roche product literature. 

 

Test

Age

Sex

Reference Range

Interpretation

eGFR-ALL

>18 years

All

≥ 90

Normal

eGFR-ALL

>18 years

All

< 60

Chronic Kidney Disease

eGFR-ALL

>18 years

All

45-59

Stage 3a

eGFR-ALL

>18 years

All

30-44

Stage 3b

eGFR-ALL

>18 years

All

15-29

Stage 4

eGFR-ALL

>18 years

All

<15

Stage 5

Note: eGFR-ALL will replace the two prior equations, one for African Americans and one for all others.  This change is based on the recognition that race is a social not a biological construct.  

References:

  1. Delgado C, et al. A unifying approach for GFR estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. J Am Soc Nephrol [published online ahead of print September 23, 2021]. doi: 10.1681/ASN.2021070988; https://jasn.asnjournals.org/content/early/2021/09/22/ ASN.2021070988
  2. Delgado C, et al. A unifying approach for GFR estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. Am J Kidney Dis [published online ahead of print September 22, 2021]. doi: 10.1053/j.ajkd.2021.08.003; https://www.ajkd.org/article/S0272-6386(21)00828-3/ fulltext
  3. Inker LA, et al. New creatinine- and cystatin C-based equations to estimate GFR without race. N Engl J Med [published online ahead of print September 23, 2021]. doi: 10.1056/NEJMoa2102953; https://www.nejm.org/ doi/10.1056/NEJMoa2102953
  4. https://www.kidney.org/kidneydisease/siemens_hcp_quickreference

 

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

82565

LOINC Codes

2160-0

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

7 days

Refrigerated

7 days

Frozen

3 months

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Creatinine

Glomerular Filtration Rate (eGFR)

Clinical Indications

The assay of creatinine in serum or plasma is the most commonly used test to assess renal function.

Methodology

Enzmatic Method, Jaffe alkaline picrate method (Roche Diagnostics)

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • Effective January 19th, 2021 a revised equation that no longer differentiates by race will be used to calculate and report estimated glomerular filtration rate (eGFR, ALL). This equation has been developed by the American Society of Nephrology and National Kidney Foundation (ASN/NKF) Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Diseases and contains the variables age, gender and plasma creatinine in its calculation.  Please note that patients may now have a change in their reported eGFR value that may require further discussion and updating of their problem list and diagnostic codes.  

New Regression Equations for eGFR, ALL based on Plasma Creatinine

  • Male
  • Pcr ≤ 0.9: eGFR = 142 * [(Pcr/0.9)-0.302] * (0.9938Age)
  • Pcr > 0.9: eGFR = 142 * [(Pcr/0.9)-1.200] * (0.9938Age)
  • Female
  • Pcr ≤ 0.7:  eGFR = 142 * [(Pcr/0.7)-0.241] * (0.9938Age) * 1.012
  • Pcr > 0.7:  eGFR = 142 * [(Pcr/0.7)-1.200] * (0.9938Age) * 1.012
  • Glomerular Filtration Rate not calculated for patients that are <18 years old.
  • Creatine: No significant interference from creatine up to a concentration of 4 mmol/L (≥ 524 mg/L).
  • Also included in Basic Metabolic Panel KPNL, Comprehensive Metabolic Panel CPNL, ER Panel I STKG, Renal Function Panel RPNL, CMP for chronic lymphocytic leukemia (CPNL FOR CLL PATIENTS ONLY) SSTCP, BMP for chronic lymphocytic leukemia (KPNL FOR CLL PATIENTS ONLY)  SSTKP

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Synonyms/Keyword Search

CREA, Creatinine, eGFR, GFREA, GFRE, CR

Last Review Date

07/19/2024

 

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