Cystatin C, Serum Concentration
This test measures the level of cystatin C, a small protein produced by all cells in your body. It helps assess your kidneys’ function.
["Cystatin C is a simple blood test to check kidney health, often used alongside other tests."]
Key facts at a glance
- LOINC
- 94823-2
- Short code
- CMV DNA Amn NAA+probe-Log#
- Synonyms
- CMV DNA Amn NAA+probe-Log#
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- probe-amp-tar
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a cystatin C test to evaluate kidney function, especially if you have symptoms like fatigue, swelling, or changes in urine output. It’s also useful in people with diabetes, high blood pressure, or a family history of kidney disease. Some doctors use it to monitor kidney health in patients with chronic conditions like heart disease or autoimmune disorders.
How Is the Test Performed?
A small blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to measure cystatin C levels. The test typically takes a few hours to complete, and results are compared to a reference range to determine if your kidneys are functioning normally.
What Do My Results Mean?
Higher than expected cystatin C levels may indicate kidney problems, while lower levels might suggest overhydration or other conditions. Your doctor will interpret results in the context of your overall health and other tests.
Common Causes of Abnormal Results
Elevated cystatin C can be caused by kidney disease, dehydration, or certain medications. Lower levels may be linked to fluid overload or conditions that reduce protein production. Other factors, like age or pregnancy, can also affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Cystatin C plays a key role in kidney function monitoring because it doesn’t depend on liver function or fluid balance like other kidney tests (like creatinine). It’s often used alongside creatinine to get a more accurate picture of kidney health, especially in people with diabetes or heart disease.
Short name
Cystatin C
Frequently asked questions
What does a cystatin C test tell me about my kidneys?
How often should I get this test?
Can diet or medications 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