Cystatin C test to assess kidney function

The Cystatin C test is a test that measures the level of the Cystatin C protein in the blood. This is a protein that can be found in most tissues and body fluids such as blood (including serum and plasma), cerebrospinal fluid, breast milk, and urine (in very small amounts).
In the body, Cystatin C performs the function of regulating and inhibiting cysteine ​​protease enzyme activity. When kidney function is normal and the kidneys are still functioning well, Cystatin C is filtered and metabolized by the kidneys, so the concentration of Cystatin C remains unchanged. However, when kidney function is impaired due to kidney failure or some other disease affecting kidney function, glomerular filtration rate declines, leading to increased concentrations of substances to be eliminated in the blood. including Cystatin C.

With the function and role of Cystatin C mentioned above, currently the Cystatin C test is indicated for the following cases:
Suspected disease affecting kidney function or creatinine test results have not been confirmed. At this time, the Cystatin test is performed to help detect functional disorders early. Monitor how patients with renal failure progress. Assess how patients with acute or chronic renal failure respond to treatment. Early detection of kidney complications due to heart failure, cardiovascular dysfunction, risk of death when combined with tests to measure serum creatinine and glomerular filtration rate (GFR). Early detection of patients with type 1 or type 2 diabetes with kidney complications. Suspected Alzheimer's disease due to manifestations of nervous system dysfunction. Suspect blood vessel damage such as atherosclerosis or aortic aneurysm.

Cystatin C test is contraindicated in the following cases:
Patients with thyroid dysfunction, then, the level of Cystatin C increases (due to hyperthyroidism) and decreases (due to hypothyroidism) affecting the thyroid gland. affect the results of the assessment of renal function. Testing should only be done when the patient has been treated for thyroid disease. Patients on hemodialysis because Cystatin C will filter out, affecting the results of kidney function assessment. Organ transplant patients because Cystatin C levels will increase due to the use of corticosteroids, affecting the results of renal function assessment.

Depending on the test unit and the method performed, the reference value for Cystatin C test results will be different. Some reference ranges of the plasma Cystatin C test that can be used are: 0.4- 1.2 mg/l; 0.8 - 2.5 mg/l.
However, the following factors can cause Cystatin C levels to rise:
Kidney damage: Renal failure, impaired glomerular filtration, kidney transplantation. Injury to the heart: Peripheral artery, myocardial infarction, heart failure. Liver disease: Progressive hepatitis. Lung injury: Pleural effusion. Joint disease Alzheimer's disease. Side effects of drugs: Long-term treatment with high doses of corticosteroids. In contrast, the results of the Cystatin C test may be reduced by the drug cyclosporin.

For kidney diseases, the Cystatin C test has specific meanings as follows:
Evaluation of glomerular filtration rate: Different from other tests, because it is not affected by factors such as height, weight , age, and sex, so Cystatin C is a specific index in assessing glomerular filtration rate. Early detection of kidney disease: The diagnostic tests for kidney disease such as urea, creatinine, ... may not change, so it does not help early detection. But the Cystatin C test is very important in the early diagnosis and detection of kidney diseases, especially before contrast-enhanced renal angiography or angiography. Screening for kidney damage: Along with other tests for kidney function, Cystatin C allows screening, assessment and monitoring of impaired kidney function in suspected cases, acute or chronic renal failure. For non-renal diseases, the Cystatin C test is meaningful in monitoring and evaluating the risk of cardiovascular disease in patients with obesity, hypertension, diabetes, ... If the test gives The increased levels of Cystatin C mean that the risk of cardiovascular damage such as heart failure, even stroke leading to death is also higher.
Cystatin C test performed together with creatinine test plays an important role in assessing kidney function in order to monitor and detect kidney damage early, especially to monitor acute renal failure as well as chronic renal failure. .
Vinmec International General Hospital is the address for examination, monitoring and treatment of many diseases. Besides, Vinmec also has a full range of tests to diagnose kidney function. With modern facilities, a system of testing machines of international standards, a team of highly qualified medical professionals will give accurate results. Thereby helping doctors advise on effective treatment directions, ensuring the health of patients.