What is cystatin C test used for?
This test measures the amount of cystatin C in blood to help evaluate kidney function. Cystatin C is filtered out of the blood by the glomeruli, clusters of tiny blood vessels in the kidneys that allow water, dissolved substances, and wastes to pass through their walls while retaining blood cells and larger proteins.
When do you check for cystatin C?
A cystatin C blood test can be helpful if:
- A previous test for kidney function was inconclusive or needs to be confirmed. In this instance, your healthcare provider may give you cystatin C test to confirm whether or not you have kidney disease.
- You are overweight, elderly or have lots of muscle (such as a body builder).
What causes high cystatin C?
If you have an abnormally high concentration of cystatin C in your blood, it may mean you may have a kidney condition, such as chronic kidney disease. Higher levels of cystatin C may also be caused by diabetes, cancer, HIV, hyperthyroidism, or hypothyroidism.
What is considered high cystatin C?
Cystatin C values for the 821 participants ranged from 0.55 mg/L to 6.59 mg/L. We categorized cystatin C into tertiles of low (≤1.230 mg/L), middle (1.231-1.710 mg/L), and high levels (>1.711 mg/L).
Do I need to fast for cystatin C?
A Cystatin C Blood Test is used to screen for and monitor kidney dysfunction in those with known or suspected kidney disease. Preparation: Fasting for 10-12 hours required.
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]
Do you need to fast for a cystatin C test?
A Cystatin C Blood Test is used to screen for and monitor kidney dysfunction in those with known or suspected kidney disease. Preparation: Fasting for 10-12 hours required. Test Results: 3-5 days. May take longer based on weather, holiday or lab delays.
What is a normal cystatin C level?
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.
What is a normal cystatin C?
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].
Is cystatin C test expensive?
And while a cystatin C test may currently cost more than a serum creatinine assay, the price of the former is not prohibitive. At Karger’s institution, the University of Minnesota, a serum creatinine test costs about $2.50, while a cystatin C assay runs about $10.60.
Why is cystatin C better than creatinine?
Like serum creatinine, cystatin C concentrations were much more stable in individuals without renal disease than was GFR measured by creatinine clearance [5]. A possible advantage of cystatin C with minor glomerular damage is that, being a large molecule, blood levels of cystatin C might rise sooner than creatinine.
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.
Why do you need a cystatin C test?
Because cystatin C levels fluctuate with changes in GFR, there has been interest in the cystatin C test as one method of evaluating kidney function.
When does cystatin C rise in the blood?
When the kidneys are functioning normally, concentrations of cystatin C in the blood are stable. However, as kidney function deteriorates, the concentrations begin to rise. This increase in cystatin C occurs as the GFR falls and is often detectable before there is a measurable decrease in kidney function (GFR).
Which is more accurate creatinine or cystatin C?
Since creatinine depends on muscle mass, assessment of kidney function may therefore not be accurate in these individuals with abnormally high or low body mass. Cystatin C is not affected by body mass or diet, and hence is a more reliable marker of kidney function than creatinine.
What causes increase in GFR and cystatin C?
A decline in kidney function leads to decreases in the GFR and to increases in cystatin C and other measures of kidney function, such as creatinine and urea in the blood. The increases in these levels occur because the kidneys are not able to properly filter the blood at a normal rate, causing their accumulation in the blood.