ABSTRACT
The level of the glomerular filtration rate (GFR) is generally accepted as the best overall index for the complex functions of the kidney in health and disease.1 This agreement holds on to functional, pathological, clinical and prognostic arguments. The functional coupling between GFR and tubular function especially relies upon the 'positive' glomerulotubular balance and the 'negative' tubuloglomerular feed-back, which ensure an integrative regulation of the whole nephron function. Similarly, the GFR decrease correlates with the extent of tubulointerstitial fibrosis and/or tubular atrophy in chronic renal diseases.2 GFR being reduced prior to the onset of symptoms of renal failure, its assessment enables earlier diagnosis and therapeutic interventions in patients at risk. Thus the level of GFR is a strong predictor of the time of onset of kidney failure as well as the risk of complications of chronic kidney disease.1 Many techniques, using either chemical or radiopharmaceuticals, exist providing either estimates or true measurements of the global GFR.
