Sulfosalicylic acid is used in urine tests to determine urine protein content. The chemical causes the precipitation of dissolved proteins, which is measured from the degree of turbidity. It is also used for integral colour anodizing.
The sulfosalicylic acid test gives a false positive reaction when x-ray contrast media, penicillins, tolbutamide, sulfasoxazole, and p-aminosalicylic acid are present in the urine. The test, appropriately, will show a positive reaction in the presence of light chains