[Detection and estimation of chronic kidney disease]

The prevalence of chronic kidney disease is increasing. An early and precise diagnosis of renal insufficiency requires a measurement of the glomerular filtration rate. Formulas based on serum creatinine to determine the glomerular filtration rate have brought, compared to serum creatinine alone, an improvement in this precision. However, in many clinical conditions, they may give incorrect information. Using 24 h urine collection, calculation of creatinine clearance can be more adequate and accurate in conditions where patient's anthropometric characteristics are far from the normal range. However, this 24 h urine collection is often variable and its validity could be criticized. When a very precise determination of glomerular filtration rate is needed, a method of reference is required such as that using chrome EDTA or iohexol. Each nephrological exploration also needs a urine analysis for detection of proteinuria. When a positive urine dipstick test is noted, a quantification of proteinuria must be done either after 24 h urine collection or more easily by determining the proteinuria/creatininuria ratio on an urine sample.