Cystatin C, Serum Concentration
This test measures the level of cystatin C, a protein produced by all cells in the body. It helps assess kidney function.
["A simple blood test to check how well your kidneys are working."]
Key facts at a glance
- LOINC
- 49466-6
- Short code
- CD2AgT
- Synonyms
- CD2 Ag Tiss Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- 10% neutral buffered formalin container for paraffin-embedded tissue specimens; sterile container for fresh or frozen tissue
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- immune-stain
- CPT
- 88342
- SNOMED
- 371440009
- Specimen volume
- Tissue biopsy specimen of adequate size (minimum 3-5 mm) to allow proper fixation, processing, and sectioning for immunohistochemical staining
- Stability
- Formalin-fixed paraffin-embedded (FFPE) tissue blocks are stable for years at room temperature. Fresh tissue should be delivered to laboratory within 1 hour or placed in appropriate transport medium. Cut sections on charged slides are stable for weeks at 2-8°C.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–72 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 used to monitor kidney disease progression or guide treatment decisions, such as for certain medications or dialysis planning.
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.
What Does the Result Mean?
Higher than expected cystatin C levels may indicate kidney problems, while lower levels could suggest other conditions. Your doctor will interpret the result in relation to your overall health and medical history.
Common Reasons for Testing
Cystatin C is often used alongside other tests (like creatinine) to get a more accurate picture of kidney function, especially in people with diabetes, high blood pressure, or a family history of kidney disease.
Reference range
Reported as Presence or Absence (Positive or Negative) of CD2 antigen expression in tissue. Normal lymphoid tissue (T-cell zones) should show positive staining in T lymphocytes. Results are interpreted by a qualified pathologist as part of immunophenotyping panels.N/A
No special patient preparation is required prior to tissue biopsy or specimen collection. Patients undergoing surgical biopsy should follow standard pre-operative instructions provided by their surgeon.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Cystatin C
Frequently asked questions
How often will I need this test?
What should I do if my results are abnormal?
Can I eat or drink anything before the 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