Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
Cystatin C
Cystatin C is the preferred kidney function marker for athletes because it is not affected by muscle mass, exercise intensity, or protein supplementation. It provides a true picture of kidney health regardless of body composition or training load.
What It Measures
This test measures the concentration of cystatin C in your blood. Cystatin C is produced at a nearly constant rate by all cells that contain a nucleus, making it a reliable indicator of kidney filtration.
Unlike creatinine, cystatin C production is not significantly affected by muscle mass, gender, or diet. This makes it particularly useful in situations where creatinine may be unreliable, such as in individuals with unusual muscle mass or dietary patterns.
Unlike creatinine, cystatin C production is not significantly affected by muscle mass, gender, or diet. This makes it particularly useful in situations where creatinine may be unreliable, such as in individuals with unusual muscle mass or dietary patterns.
Why It Matters
Cystatin C provides an independent estimate of kidney function that complements traditional creatinine-based measurements. When used together, cystatin C and creatinine offer a more accurate assessment of glomerular filtration rate than either marker alone.
This marker is especially valuable for detecting early kidney dysfunction, as cystatin C levels may rise before creatinine in the early stages of kidney disease. It can help identify kidney problems that might be missed by creatinine testing alone.
This marker is especially valuable for detecting early kidney dysfunction, as cystatin C levels may rise before creatinine in the early stages of kidney disease. It can help identify kidney problems that might be missed by creatinine testing alone.
When to Test
Cystatin C testing may be recommended when a more precise assessment of kidney function is needed, or when creatinine results may be unreliable due to factors such as extreme muscle mass, vegetarian diets, or limb amputation.
It is also valuable for early detection of kidney disease in high-risk populations, including individuals with diabetes, cardiovascular disease, or a family history of kidney problems.
It is also valuable for early detection of kidney disease in high-risk populations, including individuals with diabetes, cardiovascular disease, or a family history of kidney problems.
Symptoms
Low Levels
Low cystatin C levels are generally not clinically significant
May occasionally be seen with certain medications
Typically does not require further investigation
May occasionally be seen with certain medications
Typically does not require further investigation
High Levels
Fatigue and reduced energy levels
Swelling in the legs, ankles, or around the eyes
Changes in urination patterns
Shortness of breath
Difficulty concentrating
Swelling in the legs, ankles, or around the eyes
Changes in urination patterns
Shortness of breath
Difficulty concentrating
Recommendations
Male
If Low
Low cystatin C indicates good kidney function. No action needed.
If High
Elevated cystatin C may indicate kidney dysfunction. Consult a nephrologist for further evaluation.
Female
If Low
Low cystatin C indicates good kidney function. No action needed.
If High
Elevated cystatin C may indicate kidney dysfunction. Consult a nephrologist for further evaluation.
Lifestyle Tips
Support kidney health by staying well hydrated and maintaining a balanced diet. Manage blood pressure and blood sugar levels proactively, as cardiovascular and metabolic conditions are major contributors to kidney decline.
Avoid prolonged use of medications that can affect the kidneys without medical supervision. Maintain a healthy weight and engage in regular physical activity, as both support overall cardiovascular and renal health.
Avoid prolonged use of medications that can affect the kidneys without medical supervision. Maintain a healthy weight and engage in regular physical activity, as both support overall cardiovascular and renal health.
Frequently Asked Questions
Why is cystatin C tested instead of creatinine?
Cystatin C is less affected by muscle mass, diet, and age than creatinine, making it a more reliable indicator of kidney function in certain populations. It is often used alongside creatinine for a more accurate assessment, particularly when creatinine results may be misleading.
Can cystatin C detect kidney problems earlier than creatinine?
Yes, research suggests that cystatin C may detect early kidney dysfunction before creatinine levels begin to rise. This makes it a valuable tool for early intervention in individuals at risk of kidney disease.
Is cystatin C affected by exercise or diet?
Unlike creatinine, cystatin C is not significantly affected by muscle mass, exercise intensity, or dietary protein intake. This is one of its key advantages as a kidney function marker, particularly for athletes or individuals with unusual body composition.