[The photometric determination of total bile protein]

Studies of bilirubin absorption spectra by protein measurements with the use of the biuret test and Lowry's method have shown that bilirubin influences much the protein absorption spectrum, provoking higher results in examinations of the bile. To eliminate bilirubin effects, the authors recommend bilirubin extraction with ethyl-acetone mixture in a 1:1 ratio after protein sedimentation with trichloroacetic acid. The biuret test with bilirubin-free protein yields results compatible with those obtained by nonphotometric techniques not involving bilirubin effects.