Any method of assessing the amount or composition of protein, complex organic compounds containing carbon, hydrogen, oxygen, nitrogen, and sulfur consisting of alpha-amino acids joined by peptide linkages, in a sample of urine, the fluid waste product excreted by the kidneys, through the use of colorimetry. Colorimetry is any technique by which the color of an unknown, that is, the color of a sample, is evaluated in terms of the color(s) of a standard or a series of standards. The technique may be visual, photoelectric, or indirect by means of spectrophotometry.