Recommendations when to order or not order the test. May include related or preferred tests.
Calculate glomerular filtration rate in patients for whom serum creatinine may be misleading, such as the very obese, elderly, or malnourished patients.
Mnemonic
Unique test identifier.
CYSTAT C
Methodology
Process(es) used to perform the test.
Quantitative Nephelometry
Performed
Days of the week the test is performed.
Sun-Sat
Reported
Expected turnaround time for a result, beginning when ARUP has received the specimen.
Within 24 hours
New York DOH Approval Status
Indicates test has been approved by the New York State Department of Health.
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect
Serum Separator Tube (SST), Plasma Separator Tube (PST), or Green (Lithium or Sodium Heparin).
Specimen Preparation
Allow specimen to clot completely at room temperature. Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.4 mL)
Storage/Transport Temperature
Refrigerated.
Unacceptable Conditions
Grossly hemolyzed specimens.
Remarks
Stability
After separation from cells: Ambient: Unacceptable; Refrigerated: 1 week; Frozen: 3 months
Reference Interval
Normal range/expected value(s) for a specific disease state. May also include abnormal ranges.
Effective May 20, 2019
Test Number
Components
Reference Interval
Cystatin C
0.5 - 1.2 mg/L
eGFR by Cystatin C
Age
Reference Interval
17 years or less
Calculation not reported
18 years and greater
Stage
Description
eGFR Range (mL/min/BSA)
1
Normal or increased eGFR
90 or greater
2
Mildly decreased eGFR
60 - 89
3
Moderately decreased eGFR
30 - 59
4
Severely decreased eGFR
15 - 29
5
Kidney Failure
Less than 15
Interpretive Data
Background information for test. May include disease information, patient result explanation, recommendations, details of testing, associated diseases, explanation of possible patient results.
Compliance Category
FDA
Note
Additional information related to the test.
If the patient's age is either unknown or is 18 years or greater, then Cystatin C Reflex will be added at no additional charge.
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.
Aliases
Other names that describe the test. Synonyms.
Cystatin C, Serum with Reflex to Estimated Glomerular Filtration Rate (eGFR)
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