Test the qualitative urine protein: 3 commonly used methods for protein dipstick, sulfo salicylic acid method, heating method of acetic acid. Under normal circumstances, urine protein qualitative test was negative. But such inspection method is easily affected by some factors, can cause false results, such as high uric acid salt content, urine is acidic reaction, protein dipstick results compared with the actual situation of sulfo salicylic acid method is low, easy to false positive; extensive use of penicillin, sulfo salicylic acid method were false positive reaction; the use of iodine contrast agent sulfo salicylic acid method, heating method of acetic acid, can cause false diabetic nephropathy positive reaction; when urine is strongly alkaline, false results more, or the appearance of protein dipstick false negative reaction, false negative reaction or sulfo salicylic acid method and heating method of acetic acid. When the urine protein only renal failure for some special proteins, protein strips and sulfo salicylic acid method is not sensitive. Therefore, in the qualitative urine protein, should be integrated factors, concrete analysis of concrete conditions, choose the appropriate method. Although qualitative test is more convenient, the actual situation but sometimes difficult to reaction of proteinuria, the conditions, the best quantitative inspection.
Determination of the urinary protein quantitative: usually 24 hour urinary protein quantitative detection. More use of the method, some method is more accurate, such as Kjeldahl method, biuret method, but the operation is very complex. Current clinical use simple semi quantitative method, such as the Ai Sbachy quantitative method, sulfo salicylic acid turbidimetric method. 24 hour urinary protein quantitative between 0.15 ~ 0.5 grams of urine protein, between 0.5 to 1 grams for mild proteinuria, 1 ~ 4 grams between moderate proteinuria, greater than 4 grams (some scholars as 3.5 grams) for severe proteinuria.
Analysis of urine protein electrophoresis: commonly used methods of cellulose acetate membrane electrophoresis, polyacrylamide gel electrophoresis, protein urine immune electrophoresis. The method mainly from certain kinds of protein in urine by starting, species distinguish different urinary protein, for some difficult diseases such as multiple myeloma, heavy chain disease diagnostic and differential diagnostic significance. At the same time can molecular difference between urinary protein amount, the difference between the source of protein in the urine, and check whether there is urine plays a very important role in the special protein.