Urea (Urea) is the end product of amino acid catabolism, the molecular weight is only 61, can be freely by glomerular filtration, the original urine urea 50% is absorbed in the tubules and collecting ducts. When renal disease may be due to reabsorption decreased, the blood concentration. Another generation is better urea creatinine constant and high-protein diet significantly affected. Its meaning and the same serum creatinine, renal reserve capacity due to large, only GFR falls below 50%, blood urea will be increased.
Second, serum creatinine measurements
Serum creatinine (SCr) and includes uptake of exogenous creatine phosphate by dephosphorylation of endogenous Cr. Vivo generation amount per day with a relatively constant. After taking into account the vast majority of glomerular urine over into the original without being tubular reabsorption. Therefore, if the control uptake of exogenous Cr, Cr is preferably renal function.
Third, the serum uric acid
Uric acid (UA) for nucleoprotein and purine nucleic acid metabolite, freely through the glomerular membrane, almost all tubular reabsorption. So the blood UA concentrations consideration by glomerular and tubular excretion over the function, the function of the combined effects of reabsorption. If elevated blood UA, UA urine decreased, suggesting filtration dysfunction; blood and urine were elevated UA, UA prompted increased production, seen in primary gout; lower blood UA, UA urine increased, suggesting that tubular reabsorption disorders , seen in interstitial nephritis and the like; blood, urine UA decreased, suggesting decreased production UA, seen in acute liver necrosis, using 6-mercaptopurine, or large doses of hormones.
Fourth, the serum β-2 microglobulin
Normal daily B2-MG to generate a constant amount, free filter into the original urine, but 99% is absorbed by the proximal tubule. Elevated serum B2-MG, found in the glomerular dysfunction consider too, is more sensitive than serum creatinine; if blood, urine B2-MG increased simultaneously, but the blood B2-MG <5mg / L (renal tubular absorption threshold 5mg / L), prompted only glomerular damage, and tubular function is also impaired absorption. In addition, IgAN, cancer, inflammatory diseases, may be due to increased production of B2-MG, beyond the threshold of tubular absorption, increased urinary B2-MG.
Fifth, the cysteine protease inhibitor protein C
Cystatin C is all nucleated cells can secrete a basic protein, generated daily volume constant, low molecular weight, can be freely through the glomerular membrane, is almost completely absorbed by the proximal tubule. Linear relationship between plasma concentration and GFR was significantly better than the blood urea, Cr and Ccr, is a reflection of the glomerular dysfunction worry too early and reliable indicators. Has been recommended to replace blood urea, Cr and Ccr checks.
Six, retinol binding protein
Retinol binding protein (RBP) for blood retinol (vitamin A) transporter protein. The protein from the glomerular filtrate, absorbed by the proximal tubular degradation. RBP sensitive content changes can reflect proximal tubular function and the extent of damage, but also as an early indicator of damage and treatment monitoring of liver function. (1) reduction: vitamin A deficiency, hypoproteinemia, malabsorption syndrome, liver disease, obstructive jaundice, hyperthyroidism, infection, trauma. (2) increased: renal dysfunction, fatty liver.
Seven, homocysteine
Homocysteine is a cysteine dissimilar, was positively correlated with serum creatinine values. It can promote blood clotting factor Ⅻ, Ⅴ, platelet prostaglandin synthesis, thereby promoting platelet adhesion and aggregation, prone to cause blood clots. The lower the body homocysteine concentration, the more they can maintain a perfect body biochemical balance.
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