Examination of renal filtration function is necessary not only for detection and precise classification of chronic kidney diseases, but also to assess the associated cardiovascular risk. Both direct and, nowadays increasingly, computational methods, not requiring urine collection, are used to determine the glomerular filtration rate.
In higher age gradual but significant decline of renal functions occurs. Therefore some computational methods for estimating glomerular filtration rate may provide inaccurate results in the elderly.
This is especially true for equations derived from non-standardized serum creatinine. A promising method is to estimate glomerular filtration rate on the basis of serum cystatin C.