Kidney & Electrolytes
Cystatin C
Kidney & Electrolytes
Kidney function marker. More accurate than creatinine, unaffected by muscle mass.
VAT-exempt medical service
Cystatin C is produced at a steady rate by virtually all cells in the body and is removed from the blood exclusively by the kidneys. Because its production is not significantly affected by muscle mass, diet, or sex, it provides a more accurate picture of kidney function than creatinine alone. Emerging research also links cystatin C to cardiovascular risk and new-onset diabetes.
Testing cystatin C is recommended when you want an unbiased view of kidney health -- especially if your muscle mass is unusually high or low, making creatinine less reliable. It is also valuable for anyone with risk factors such as heavy alcohol use, a nutrient-poor diet, diabetes, or cardiovascular disease. Repeated measurements help track the effect of lifestyle changes and treatment.
What a high value can mean
Elevated cystatin C corresponds to a decreased glomerular filtration rate (GFR) and points to reduced kidney function. Causes include chronic kidney disease, diabetes, hyperthyroidism, osteoporosis, and systemic inflammation. Recent studies also associate high cystatin C with increased risk of heart failure and mortality.
What a low value can mean
Low cystatin C is rare and not well understood. It may occasionally occur in conditions involving rapid muscle loss or severe malnutrition. Discuss unexpectedly low results with your doctor.
No preparation is needed. Bring valid ID to your appointment.
Order your test
Choose your test and pay online. Your lab referral is created straight away.
Give your sample
Visit any of our partner sampling locations. No appointment needed at most of them.
The lab analyses it
Your sample is analysed at an accredited Swedish laboratory.
Get your results
Your values appear in your account with reference ranges and an explanation of each marker.
Creatinine levels are influenced by muscle mass, age, sex, and diet, which can skew results. Cystatin C is produced at a constant rate regardless of these factors, making it a more reliable kidney marker in many cases.
Yes. Elevated cystatin C has been linked to increased cardiovascular risk, heart failure, and mortality in several studies, even in people without known kidney disease.
Testing both can give a more complete picture. If the two results differ significantly, it can help your doctor pinpoint whether the issue is kidney-related or influenced by muscle mass.
This combination may indicate systemic inflammation rather than isolated kidney dysfunction. Additional inflammatory markers such as ESR or IL-6 can help clarify the situation.