The Protein Test Strips detect residual protein in water in increments of 0.3, 1.0, 3.0, 10.0 plus g/L. If used to test protein in the urine, the colour may be more green than blue. If testing urine samples, consider using the Urine Analysis Test Strip. The Protein Test Strip is based on the so-called "protein error of indicators". This phenomenon relates to the fact that certain pH indicators will change the colour at a different pH value in the presence of protein than in the absence of protein. The test is more sensitive to albumin than to globulins, mucoproteins, hemoglobin and Bence-Jones protein.