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Urinary proteins
• Increased excretion of proteins in the urine, i.e. proteinuria(＞120mg/24h), is the hallmark of the almost any kind of kidney disease.
lower mol wt proteins.
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The reason of proteinuria
Approximate size cutoff of substances for filtration is 70kDa.
• substances smaller than this are often retained,either due to charge effects(albumin) or because they are tightly bound to other proteins to give them a larger effective size
• It is not known for how long the urine was present in the bladder.
• The interpretation of the findings is difficult.
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First morning(8-h specimen) urine
• Simple and inexpensive.
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• Dipsticks detect protein by production of color with an indicator dye, Bromphenol blue, which is most sensitive to albumin but detects globulins and Bence-Jones protein poorly. Precipitation by heat is a better semiquantitative method, but overall, it is not a highly sensitive test. The sulfosalicylic acid test is a more sensitive precipitation test. It can detect albumin, globulins, and Bence-Jones protein at low concentrations.
