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Cystatin C Blood Test

Last updated Oct. 11, 2015

What are the other Names for this Test? (Equivalent Terms)

  • Gamma Trace Blood Test
  • Neuroendocrine Basic Peptide Blood Test
  • Post-Gamma Globulin Blood Test 

What is Cystatin C Blood Test? (Background Information)

  • Cystatin C is a small protein, found in nearly all cells of the body. It helps regulate the activity of degradative enzymes (enzymes that breakdown larger molecules) in and around these cells. Clinically, cystatin C is used as a marker for kidney function
  • The kidneys, along with the liver and spleen, filter blood and excrete the waste as urine. The site of filtration is a microscopic sieve-like structure in the kidney, called the glomerulus. There are roughly 1 million glomeruli in each kidney. The rate at which glomeruli filter blood is called the glomerular filtration rate (GFR)
  • When the kidneys and glomeruli are damaged, GFR may decrease. Decreased GFR may result in the accumulation of proteins, such as cystatin C and creatinine in blood
  • The Cystatin C Blood Test is a test to measure the levels of cystatin C in circulation. It is used to assess the glomerular filtration rate, which indirectly provides an assessment of the kidney function 

What are the Clinical Indications for performing the Cystatin C Blood Test?

Following are the clinical indications for performing a Cystatin C Blood Test:

  • Evaluating kidney disease (both acute and chronic renal disorders)
  • Yellowing of skin
  • Discolored urine
  • Difficulty urinating
  • Urinating more often or less often than usual 

How is the Specimen Collected for Cystatin C Blood Test?

Following is the specimen collection process for Cystatin C Blood Test:

Sample required: Blood

Process: Insertion of a needle into an arm vein.

Preparation required: No special preparation is needed prior to the test. 

What is the Significance of the Cystatin C Blood Test Result?

  • Increased cystatin C levels may indicate kidney dysfunction, due to a variety of causes 

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario. 

Additional and Relevant Useful Information:

  • Cystatin C has been shown to vary less with factors, such as age, race, and muscle mass, than creatinine, which is the currently used indicator for kidney function. The two tests are often performed together
  • The Cystatin C Blood Test may also provide clues to cardiovascular health, as cystatin C levels are decreased with cardiovascular diseases, like atherosclerosis 

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis. 

What are some Useful Resources for Additional Information?

DoveMed is currently working to bring you additional resources.

Please sign up by creating a DoveMed account to receive periodic notification on information updates. 

References and Information Sources used for the Article:

Lab Tests Online (2014, April 3). Retrieved July 29, 2014 from http://labtestsonline.org/understanding/analytes/cystatin-c/

Mayo Clinic. (2011, January). Use of cystatin C to assess kidney function. Retrieved July 29, 2014 from http://www.mayomedicallaboratories.com/index.html

Shlipak, M. (2013). Cystatin C versus creatinine in determining risk based on kidney function. The New England Journal of Medicine369(10), 932-43. 

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Aug. 1, 2014
Last updated: Oct. 11, 2015