[Diagnostic approach prior to the onset of chronic renal insufficiency]

Chronic nephropathies are usually asymptomatic and should therefore be systematically depisted, especially in "high risk" patients. These subgroups of patients have been relatively well defined as subjects with hypertension, diabetes and ageing. A plasma creatinine concentration of 150 mumol/L can easily diagnose chronic renal failure with an absolute specificity (100% of the subjects do have a glomerular filtration rate beneath 80 mL/min). This threshold however is too high as some patients may already exhibit a significant reduction in renal function. "Corrected" creatinine, i.e., computing creatinine clearance using the Cockcroft's formula allows a more reliable estimation of glomerular filtration rate. The long term prognosis of chronic renal failure is far from good. The progression rate is higher in patients with persistent hypertension and heavy proteinuria that are themselves amenable to symptomatic therapies. Timely nephrologic referral is a warrant of optimal care.