Lab Test

Creatinine

GFR, Serum Creatinine, Creatinine, Serum (includes estimated Glomerular Filtration Rate - eGFR)

Test Codes

Antrim #17119, EPIC: LAB5023, SOFT: CREAT

Specimen Collection Criteria

FOR EC AND INPATIENT SAMPLE COLLECTION ONLY:

Preferred Sample:  One Light Green Top Plasma Separator Tube (PST)(Minimum Whole Blood: 4.0 mL)

Acceptable Sample:  One Gold Top SST (Minimum Whole Blood:  4.0 mL)

FOR PHYSICIAN OFFICE/OUTREACH SAMPLE COLLECTION:

COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL) 

Contact Laboratory for acceptability of other tube types.
See Minimum Pediatric Specimen Requirements for Microtainer® collection.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2–8°C or 36–46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2–8°C or 36–46°F). (Minimum: 0.5 mL)

Rejection Criteria

Moderate to grossly hemolyzed specimens.

Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers® to separate serum from cells. Deliver immediately to the appropriate testing station.


Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2–8°C or 36–46°F): 7 days

Laboratory

Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 4 hours.

Reference Range

Creatinine Reference Range:

Age   Female (mg/dL) Male (mg/dL) 
0 – 14 Days 0.32 – 0.92 0.32 – 0.92
15 Days – <2 Years 0.10 – 0.36 0.10 – 0.36
2 – <5 Years 0.20 – 0.43 0.20 – 0.43
5 – <12 Years 0.31 – 0.61 0.31 – 0.61
12 – <15 Years 0.45 – 0.81 0.45 – 0.81
15 – <19 Years 0.49 – 0.84 0.62 – 1.08
 19 – Adult  0.50 – 1.10  0.60 – 1.30

 

Test Methodology

Spectrophotometry.

Interpretation

  • Creatinine levels can be increased due to decreased blood flow to the glomeruli (perfusion deficiencies), renal disease (glomerulonephritis, pyelonephritis) or post renal obstruction (stone, tumor). Because the creatinine is an insensitive indicator of renal impairment increased plasma levels usually signify a loss of more than 50% of kidney function.
  • Decreased levels can be seen in pregnancy and patients with decreased muscle mass due to age or other causes.
  • Creatinine methods at Grosse Pointe, Royal Oak and Troy are standardized against IDMS (Isotope Dilution Mass Spectrometry).
  • Except for Creatinine Clearance reporting, a calculated glomerular filtration rate will be included whenever a serum creatinine is ordered on individuals 18 years and older.

Effective September 8, 2015, Beaumont Laboratory uses the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation to calculate estimated glomerular filtration rate (eGFR). Prior to this date, the MDRD equation (Modification of Diet in Renal Disease) was used. Both equations take into account the patient's serum creatinine, age, sex, and race. However the CKD-EPI equation is more accurate than the MDRD equation for eGFRs between 60 and 120 mL/min/1.73m2. We will continue to report an eGFR for both African-American and non-African-American patients.

CKD-EPI Equation: GFR = 141 x min (Scr/k, 1)α x max(Scr/k, 1)-1.209 x 0.993Age x 1.018 (if female) x 1.159 (if black) where:

  • Scr is serum creatinine in mg/dL.
  • K is 0.7 for females and 0.9 for males.
  • α is -0.329 for females and -0.411 for males.
  • Min indicates the minimum of Scr/K or 1.
  • Max indicates the maximum of Scr/K or 1.

For your reference, the stages of kidney disease will be included on all reports:

G1: Normal GFR - Greater than 90 mL/min/1.73m2.
G2: Mildly decreased GFR - 60-89 mL/min/1.73m2.
G3a: Mildly to moderately decreased GFR - 45-59 mL/min/1.73m2.
G3b: Moderately to severely decreased GFR - 30-44 mL/min/1.73m2.
G4: Severely decreased GFR - 15-29 mL/min/1.73m2.
G5: Kidney failure - GFR less than 15 mL/min/1.73m2.

Please note that the result is normalized to 1.73 m2, an accepted average adult Body Surface Area (BSA). Therefore, the result may not be valid for patients with very abnormal body composition (e.g. very muscular patients with a high BSA may have their GFR under-estimated, and the converse for obese patients) and for those with limb amputations (whose low muscle mass would result in an over-estimation of their GFR). eGFR is most useful for patients with stable kidney function.

Clinical Utility

The quantitative determination of creatinine aids in the diagnosis and treatment of renal diseases, in monitoring renal dialysis, and as a calculation basis for measuring other urine analytes. It is most sensitive in detecting renal impairment when used as part of a Creatinine Clearance test.

Reference

  1. Definition and Classification of Stages of Chronic Kidney Disease. Am J Kidney Dis. 2002;39, No 2 supplement 1 pp S46-75.
  2. Levey, et al., Ann Int Med 2009; 150: 604-12.
  3. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Disease. Kidney Inter., Suppl. 2013; 3: 1-150.

CPT Codes

82565

Contacts

Last Updated

11/9/2020

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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.