Cystatin C, Serum Concentration
This test measures the level of cystatin C, a protein produced by all cells in your body. It helps assess kidney function and can be useful in monitoring chronic conditions.
["Cystatin C helps evaluate kidney health and may be used alongside other tests for better accuracy."]
Key facts at a glance
- LOINC
- 11785-3
- Short code
- Cvx canal ext Os Diam US.meas
- Synonyms
- Cvx canal ext 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 Is This Test Done?
Your healthcare provider may order this test to check how well your kidneys are working. It can also be used to monitor kidney function in people with conditions like diabetes or high blood pressure. Cystatin C is often used in combination with other tests, such as creatinine, to get a clearer picture of kidney health.
What Does a High or Low Level Mean?
Higher than expected levels of cystatin C may suggest kidney problems, including reduced kidney function. Lower levels might indicate other health factors, though this is less common. Your results will be compared to what’s typical for your age and health status.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The sample is sent to a lab where it’s analyzed to measure cystatin C levels. No special preparation is usually needed, but you may be asked to avoid certain foods or medications for a short time before the test.
What Are the Possible Results?
Results are expressed in units of concentration (typically mg/L or µmol/L). Your doctor will interpret these results in relation to your overall health and medical history. Some labs may provide a qualitative or semi-quantitative assessment rather than a precise number.
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 much with muscle mass or diet. It’s often used in conjunction with creatinine to improve the accuracy of kidney function assessments, especially in people with diabetes or other chronic conditions. High levels may indicate early kidney damage, while persistently low levels are less commonly associated with clinical significance.
Short name
Cystatin C
Frequently asked questions
How often should I get this test?
What does it mean if my cystatin C level is higher than usual?
Can diet or exercise affect cystatin C levels?
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