Qualitative tests are used to screen and roughly estimate the amount of urine protein. There are three methods of testing: the test paper method, the sulforaphane method, and the heated acetic acid method. Both the sulforaphane method and the heated acetic acid method are based on a turbidity reaction that designates the absence of turbidity or precipitation as negative (I) and the presence of turbidity or precipitation as positive (+). The sulfosalic acid method is easy to operate and highly sensitive, and can be widely used for census, but its sensitivity for albumin is higher than that for globulin, and there are more influencing factors, which can easily cause false negatives or false positives. The sensitivity of the heated acetic acid method is basically the same for albumin and globulin, with fewer influencing factors and higher accuracy. The amount of urine protein is estimated from the turbidity response as follows: Urine protein 4.0 g/L: ++++. Normal urine contains trace amounts of protein (24-hour urine protein quantification)