What is the importance of cystatin C as a marker for GFR?
Cystatin C is effectively filtered by the glomerulus and fully reabsorbed and broken down by the renal tubules for recycling. A raised level of serum or plasma cystatin C correlates closely with the GFR. Cystatin C therefore acts as an excellent indicator of reduced kidney function.
What is the advantage of cystatin C over 24 hour urine creatinine clearance for monitoring GFR?
As GFR decreased from 120 to 20 mL/min/1.73 m2, cystatin C increased more significantly that serum creatinine, giving a stronger signal in comparison to that of creatinine over the range of the measured GFR.
What is the normal range for cystatin C?
The range for cystatin C is 0.67-6.15 mg/l, 0.66-7.23 mg/dl for creatinine and 8.9-186.3 l/day (6.2-129.4 ml/min) for creatinine clearance. Serum cystatin C levels started to increase over normal range when creatinine clearance fell below 135.9 l/day (94.4 ml/min), while serum creatinine remained within normal ranges.
Is cystatin C more accurate than creatinine?
The maximum diagnostic accuracy of serum cystatin C (90%) was significantly better than those of serum creatinine (77%) and Cockcroft and Gault estimated GFR (85%) in discriminating between type 2 diabetic patients with normal GFR (>80 mL/min per 1.73 m2) and those with reduced GFR (<80 mL/min/1.73 m2).
What is the function of cystatin C?
Cystatin C is a low molecular-weight protein (13,000 Da) that is produced by all nucleated cells and acts to inhibit cysteine proteases. It has been used as an estimate of the severity of CKD because a high level of cystatin C is associated cardiovascular disease and may even be more closely associated than SCr.
What is cystatin C test used for?
Cystatin C can be used to calculate your glomerular filtration rate (GFR). Your healthcare provider can use this to see how well your kidneys are working and if there is a problem. It can also be used to check the progress of your disease, if you have kidney problems.
When would you use cystatin C over creatinine?
Recent guidelines suggest the use of cystatin C to validate the diagnosis of chronic kidney disease in patients who are currently considered to have chronic kidney disease solely on the basis of a creatinine-based eGFR of less than 60 ml per minute per 1.73 m2, without albuminuria or other markers of kidney damage.
What does cystatin C do?
What is a good cystatin C level?
The normal range of cystatin C is around 0.62 – 1.15 mg/L. Values can vary between laboratories. Generally, higher cystatin C levels point to poor kidney function [7].
What is a high cystatin C level?
A high level of cystatin C in the blood corresponds to a decreased glomerular filtration rate (GFR) and hence to kidney dysfunction.
How accurate is GFR?
The accuracy of GFR estimation formula was taken as positive if the GFR calculated by the formulas and urine creatinine clearance fell between 90-120 mL/min/1.73 m(2). The accuracy of the MDRD formula was 48.8% and the CG formula was 41.5% whereas the accuracy of the CKD-EPI formula was 78.2%.
What does a low cystatin C mean?
Lower cystatin C levels have been associated with a higher risk of: Cognitive dysfunction and Alzheimer’s disease [4, 97, 98] Hardening of the arteries (atherosclerosis) [13, 9] Aneurysms [13, 99]
What is cystatin C and how is it used to measure GFR?
Like creatinine, the cystatin C number is used in a math formula with your age, race, and gender to estimate your GFR. The cystatin C test is not the usual or regular way that your healthcare provider will estimate your GFR. But it can be very helpful in some instances. When is cystatin C used to estimate GFR?
What is a blood test for cystatin C?
A blood test for cystatin C can help your healthcare provider find your GFR (glomerular filtration rate). Your GFR number helps your healthcare provider know how well your kidneys are working. What is GFR (glomerular filtration rate)? Your GFR tells a lot about how well your kidneys are working. Your kidneys are important.
How do you estimate your GFR?
Another way to estimate GFR is with a simple blood test for cystatin C. Like creatinine, the cystatin C number is used in a math formula with your age, race, and gender to estimate your GFR. The cystatin C test is not the usual or regular way that your healthcare provider will estimate your GFR.
How is creatinine related to GFR?
Creatinine is a waste product made by your body’s muscles. Your kidneys usually keep the level of creatinine just right. The level of creatinine in your blood and your age, race, and gender are used in a math formula to estimate your GFR. Another way to estimate GFR is with a simple blood test for cystatin C.