Cystatin C (Serum) Concentration, Quantitative
This test measures the level of cystatin C, a protein produced by all cells in the body that helps regulate cell growth and repair. It’s often used to assess kidney function.
["Cystatin C helps evaluate how well your kidneys are working."]
Key facts at a glance
- LOINC
- 11787-9
- Short code
- Cvx canal Int Os Diam US.meas
- Synonyms
- Cvx canal Int Os Diam US.meas
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-measured
- CPT
- 86038
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test to check for kidney disease, monitor kidney function over time, or evaluate kidney damage in conditions like diabetes or high blood pressure. It can also be used alongside other tests to help diagnose or manage chronic kidney disease.
How the Test Works
A small blood sample is taken from a vein in your arm. The sample is sent to a lab where cystatin C levels are measured using a sensitive immunoassay method. This test provides a more accurate picture of kidney function compared to traditional tests like creatinine alone.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have some mild discomfort from the needle, but it usually goes away quickly. If you’re on blood thinners or have a history of bleeding disorders, let your doctor know before the test.
What the Results Mean
While specific reference ranges vary by lab, higher cystatin C levels may indicate reduced kidney function. Your doctor will interpret the results in the context of your overall health, other tests, and medical history to determine if further action is needed.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Cystatin C is a reliable marker for kidney function because it’s produced by all cells and doesn’t change with muscle mass or hydration levels. It’s particularly useful for detecting early kidney damage, especially in people with diabetes or those at higher risk for kidney disease. Your doctor may use it to guide treatment decisions, such as adjusting medications or monitoring progression of kidney disease.
Short name
Cystatin C
Frequently asked questions
How often will I need this test?
Can I eat or drink before this test?
Will this test affect my medications?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy