L'exploration du rein en 2013

Kidney exploration mainly concerns the exploration of its excrétion and endocrine functions. The exploration of rénal excrétion functions in 2013 takes into considération of plasma créatinine supremacy for measuring glomerular filtration rate as well alone as associated with urine créatinine, or included in a particular score, such as Cockcroft-Gault score, MDRD or CKD-EPI. New biomarkers appeared recently such as NGAL, which could supplant markers that did not surface at now such as cystatin C and β2-microglobulin. Kidney tubular functions are explored by the measure of both plasma and urine osmolalities, as well as pH and chloride measurements in urines. Urinary ionogram takes a big place for differentiation between organic rénal failure (RF) and functional RF. Urine analysis is more and more important with the study of its protein content and of rénal stones, without neglecting the use of urine dips-ticks allowing the détection of diabètes, urine infection, organic kidney disease and many other pathological situations. New urine biomarkers arose such as KIM-1, but we can also remark the increase in the use of urine cystatin C and NGAL, alone or coupled to their détermination in plasma. The exploration of endocrine functions of kidney regards (1) renin-angiotensin-aldosteronesys-tem as activated in renovascular arterial hypertension and hyperaldosteronism, (2) kallicrein-kinin System as well as prostaglandins from renai origin in inflamma-tory and oedematous pathologies, (3) erythropoietin in anemia related to RF and in polycystic kidney disease, (4) the métabolites of D vitamin, mainly calcitriol, since its defect related to RF is the cause of hypocalcemia, f ibrotic osteitis and less frequently nephrocalcinosis. The kidney also exerts metabolic functions; in particular, in RF patients we must contrai regularly glycaemia, lipid parameters and thyroid. In certain circumstances, we might detect sérum auto-antibodies or immune complexes in kidney biopsies.