Detection of early renal dysfunction remains a difficult problem because
creatinine levels often do not become abnormal until glomerular filtration rate is severely reduced.
Creatol, which also accumulates in
renal failure, has been suggested as an alternative to
creatinine. To measure glomerular filtration rate, a number of simplified techniques have been suggested; for the most part, however, they have not been validated in patients with severe
chronic renal failure. Glomerular filtration rate can be estimated with fair precision from serum
creatinine concentration with the use of improved equations, provided that the serum
creatinine level is greater than 2 mg/dL. The use of
cimetidine to reduce the discrepancy between
creatinine clearance and glomerular filtration rate does not seem justifiable. In
diabetic nephropathy, sequential biopsies may be preferable to sequential determinations of glomerular filtration rate for follow-up of patients with this disease.