QUANTITATIVE ASSESSMENT OF GLOMERULAR PERMEABILITY PROTEINURIA

Sample Collection for Total Protein and Albumin Measurement 

Although the reference point remains the accurately timed 24-hour specimen, it is widely accepted that this is a difficult procedure to control effectively studies have shown that more than 25% of samples have to be discarded because an incomplete collection is suspected. In practice, for screening purposes, spot urine protein/creatinine ratios (or 

Measurement of Total Protein There are numerous methods used for the measurement of protein in urine (see Chapter 20). They include (1) the original Lowry method,(2) turbidimetry after mixing with trichloroacetic or sulfosalicylic acid, (3) turbidimetry with benzethonium chloride (benzyl dimethyl (2-[2-(p-1,1,3,3-tetramethyl butylphenoxy)ethoxy]ethyl ammonium chloride,(4) dye binding with Coomassie Brilliant Blue, and (5) dye binding with pyrogallol red molybdate.  

The normal urinary total protein excretion is less than 150mg/24hr. The proteins excreted are made up of mostly albumin (50% to 60%) and some smaller proteins, together with proteins secreted by the tubules, of which Tamm-Horsfall glycoprotein (THG) is one. The normal concentrations of proteins found in urine are listed in Table 24-1. 

NORMAL URINE CONTAINING LESS THAN 0.06g/L PROTEIN 

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