About Cystatin-C
Cystatin-C is a protein that is produced by all nucleated cells in the body and is considered a marker for evaluating kidney function. Unlike creatinine, its production is not influenced by muscle mass, making it a potentially more reliable marker for assessing the glomerular filtration rate (GFR). It has been found to offer improved accuracy in detecting early kidney impairment, reflecting overall kidney health.
Reference Values
Optimal Range
0 - 0.7 mg/L
Elite Value
0.7 mg/L
Health Implications
High
Elevated levels may indicate reduced kidney function, potentially signaling chronic kidney disease or acute kidney injury.
Low
Low levels may be associated with a hyper-metabolic state, such as hyperthyroidism, where the body uses proteins more rapidly.
Symptoms
High
May include fatigue, headaches, swelling in extremities, and difficulty breathing.
Low
Can include dizziness, weakness, muscle cramps, and confusion.
Lifestyle Factors
Specimen Type
Testing Methods
Also Known As
Scientific Sources
- Shlipak, M. G., Matsushita, K., Ärnlöv, J., Inker, L. A., Katz, R., Polkinghorne, K. R., ... & Levey, A. S. (2013). Cystatin C versus creatinine in determining risk based on kidney function. *New England Journal of Medicine*, 369(10), 932-943.
- Inker, L. A., Schmid, C. H., Tighiouart, H., Eckfeldt, J. H., Feldman, H. I., Greene, T., ... & Levey, A. S. (2012). Estimating glomerular filtration rate from serum creatinine and cystatin C. *New England Journal of Medicine*, 367(1), 20-29.
- Grubb, A., Blirup-Jensen, S., Lindström, V., Schmidt, C., Althaus, H., & Zegers, I. (2010). First certified reference material for cystatin C in human serum ERM-DA471/IFCC. *Clinical Chemistry and Laboratory Medicine*, 48(11), 1619-1621.
- tional Kidney Foundation. (2021). Cystatin C. Retrieved from
- Levey, A. S., Stevens, L. A., Schmid, C. H., Zhang, Y. L., Castro, A. F., Feldman, H. I., ... & Coresh, J. (2009). A new equation to estimate glomerular filtration rate. *Annals of Internal Medicine*, 150(9), 604-612.