常用肾脏功能实验室检测讲述.ppt

Mechanism BUN reabsorption is increased. BUN is disproportionately elevated relative to creatinine in serum. Dehydration is suspected. Normal range. Can also be postrenal disease. BUN reabsorption is within normal limits. Renal damage causes reduced reabsorption of BUN, therefore lowering the BUN:Cr ratio. * * * * * * * * * * * * * * Synthesis in liver Urine RBP: proximal tubular reabsorption uRBP is a glycoprotein that belongs to the alpha-globulin family and it is a low molecular weight enzyme (approximately 21.0 kDa) produced by hepatocytes * Synthesis in liver Urine RBP: proximal tubular reabsorption N-acetyl-β-d-glucosaminidase N-acetyl-β-d-glucosaminidase (NAG) is a lysosomal brush border enzyme found in proximal tubular cells. It is relatively big (?130 kDa) and is therefore not filtered through the glomerular membrane [78–80]. NAG has been shown to function as a marker of kidney injury, reflecting particularly the degree of tubular damage [80]. It is not only found in elevated urinary concentrations in acute and chronic kidney disease but also in diabetic patients, patients with essential hypertension and HF [83–86]. In selected patient populations, patients with higher NAG levels do not only suffer more frequently from acute renal dysfunction but also more often experience albuminuria and more severe structural renal damage [87]. In patients with acute renal failure, urinary NAG independently predicted the occurrence of hospital death or need for dialysis [80]. In primary glomerulonephritis, urinary NAG levels were significant predictors of functional outcome [81,82]. * * * * * * * * Clinical Significance of Ccr Physiological ： related with sports, diets, age…… Pathological decrease Sensitive for kidney injury GFR50%时 Ccr≈50ml/min Stage of renal failure * 10-20ml/min 20-50ml/min 50ml/min 80ml/min Stage 4 (Failure stage) Stage 3 (De-compensatory stage) Stage 2 (Compensatory stage) Stage 1 (Normal function) 10ml/min Stage 5 (Uremia) C