Search our extensive Laboratory Test Directory to find test codes, ordering recommendations, specimen stability information, Test Fact Sheets, and more.
Recommendations when to order or not order the test. May include related or preferred tests.
Use to calculate glomerular filtration rate when serum creatinine may be misleading, e.g., in individuals who are elderly, have severe obesity, or are malnourished.
New York DOH Approval Status
Indicates whether a test has been approved by the New York State Department of Health.
This test is New York state approved.
Specimen Required
Patient PreparationInstructions patient must follow before/during specimen collection.
CollectSpecimen type to collect. May include collection media, tubes, kits, etc.
Specimen PreparationInstructions for specimen prep before/after collection and prior to transport.
Allow serum tube to clot completely at room temperature. Separate serum or plasma from cells within 2 hours of collection. Transfer 1 mL plasma or serum or plasma to an ARUP standard transport tube. (Min: 0.2 mL)
Storage/Transport TemperaturePreferred temperatures for storage prior to and during shipping to ARUP. See Stability for additional info.
Refrigerated.
Unacceptable ConditionsCommon conditions under which a specimen will be rejected.
Blood collected in capillary blood collection tubes is unsuitable for use in this assay.
RemarksAdditional specimen collection, transport, or test submission information.
Patient age and sex are required for calculation.
StabilityAcceptable times/temperatures for specimens. Times include storage and transport time to ARUP.
After separation from cells: Ambient: 7 days; Refrigerated: 7 days; Frozen: 3 months
Expected turnaround time for a result, beginning when ARUP has received the specimen.
Within 24 hours
Reference Interval
Normal range/expected value(s) for a specific disease state. May also include abnormal ranges.
Test Number
Components
Reference Interval
eGFR by CKD-EPI Creatinine-Cystatin 2021
>= 60
Cystatin C
Age
Male
Female
0 Year
0.84 - 1.29 mg/L
0.84 - 1.26 mg/L
1 Year
0.77 - 1.18 mg/L
0.78 - 1.16 mg/L
2 Year
0.70 - 1.07 mg/L
0.70 - 1.04 mg/L
3 Year
0.68 - 1.02 mg/L
0.67 - 1.00 mg/L
4 Year
0.68 - 1.02 mg/L
0.68 - 1.01 mg/L
5 Year
0.68 - 1.03 mg/L
0.69 - 1.03 mg/L
6 Year
0.69 - 1.04 mg/L
0.70 - 1.04 mg/L
7 Year
0.68 - 1.05 mg/L
0.70 - 1.04 mg/L
8 Year
0.69 - 1.05 mg/L
0.71 - 1.04 mg/L
9 Year
0.69 - 1.06 mg/L
0.71 - 1.05 mg/L
10 Year
0.70 - 1.07 mg/L
0.72 - 1.07 mg/L
11 Year
0.71 - 1.08 mg/L
0.72 - 1.10 mg/L
12 Year
0.73 - 1.12 mg/L
0.72 - 1.11 mg/L
13 Year
0.76 - 1.17 mg/L
0.70 - 1.09 mg/L
14 Year
0.78 - 1.19 mg/L
0.68 - 1.07 mg/L
15 Year
0.78 - 1.18 mg/L
0.66 - 1.05 mg/L
16 Year
0.77 - 1.15 mg/L
0.65 - 1.03 mg/L
17 Year
0.74 - 1.11 mg/L
0.64 - 1.01 mg/L
>= 18 Years
0.61 - 0.95 mg/L
0.61 - 0.95 mg/L
Interpretive Data
May include disease information, patient result explanation, recommendations, or details of testing.
Calculated GFR - >= 60 mL/min / 1.73 square meters The estimated glomerular filtration rate (eGFR) was calculated using the 2021 CKD-EPI eGFR creatinine-cystatin equation. This equation is validated in individuals 18 years of age and older. Accurate estimation of GFR requires stable day-to-day filtration markers (creatinine and cystatin C). Filtration markers are influenced by non-GFR determinants, including generation from cells and diet, tubular secretion and reabsorption, and extra-renal elimination. These determinants may affect eGFR accuracy. The eGFR is normalized to a body surface area of 1.73 square meters.
GFR Categories in Chronic Kidney Disease (CKD)
GFR Category
GFR (mL/min/1.73 square meters)
Interpretation
G1
90 or greater
Normal to high*
G2
60-89
Mild decrease*
G3a
45-59
Mild to moderate decrease
G3b
30-44
Moderate to severe decrease
G4
15-29
Severe decrease
G5
14 or less
Kidney failure
*In the absence of evidence of kidney damage, neither GFR category G1 nor G2 fulfill the criteria for CKD (Kidney Int Suppl 2013;3:1-150)
The American Medical Association Current Procedural Terminology (CPT) codes published in ARUP's Laboratory Test Directory are provided for informational purposes only. The codes reflect our interpretation of CPT coding requirements based upon AMA guidelines published annually. CPT codes are provided only as guidance to assist clients with billing. ARUP strongly recommends that clients confirm CPT codes with their Medicare administrative contractor, as requirements may differ. CPT coding is the sole responsibility of the billing party. ARUP Laboratories assumes no responsibility for billing errors due to reliance on the CPT codes published.
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
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