Cystatin C, Serum Concentration
This test measures the level of cystatin C, a protein produced by all cells in your body, in your blood. It helps assess kidney function.
["Cystatin C helps monitor kidney health and may be used alongside other tests to evaluate kidney function over time."]
Key facts at a glance
- LOINC
- 59226-1
- Short code
- CGA-PF
- Synonyms
- CgA Prt-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container without additives (red-top or plain tube for fluid transfer); specific containers provided by the testing laboratory should be used
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Immunoassay (ELISA or chemiluminescence)
- CPT
- 83520
- SNOMED
- 313604002
- Specimen volume
- 2-5 mL of peritoneal fluid
- Stability
- Refrigerated (2-8°C): 48 hours; Frozen (-20°C or below): 3 months. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 72–168 hours
- Order
- routine
What Does This Test Measure?
Cystatin C is a small protein that your body produces continuously. Unlike traditional kidney function tests like creatinine, cystatin C levels are less affected by muscle mass or diet. Your doctor may use this test to check how well your kidneys are filtering waste products from your blood, especially if you have conditions like diabetes, high blood pressure, or kidney disease.
Why Might You Need This Test?
Your healthcare provider may order a cystatin C test if you have symptoms of kidney problems, such as swelling, fatigue, or changes in urine output. It may also be used to monitor kidney function in people with chronic conditions or those taking medications that can affect kidney health.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure cystatin C levels. This test typically requires no special preparation, but you may be asked to avoid certain medications or foods for a short time if instructed by your doctor.
What Do the Results Mean?
Results are not provided with specific numeric ranges here, as reference intervals can vary by lab and patient factors. Your doctor will interpret the results in relation to your overall health and medical history to determine if your kidney function is normal or if further action is needed.
Reference range
Reference ranges for Chromogranin A in peritoneal fluid are not well established; clinical interpretation should be made in correlation with serum levels and clinical findings. Elevated levels may suggest neuroendocrine tumor involvement or peritoneal metastasis.N/A
No special patient preparation required. However, proton pump inhibitors (PPIs) should be discontinued for at least 1-2 weeks prior to testing if possible, as they may falsely elevate Chromogranin A levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Cystatin C Blood Test
Frequently asked questions
How often should I get this test?
What can affect my cystatin C levels?
Can I prepare for this test?
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