Quantification of the ratio of 3-Indolepropionic acid to cis-5,8,11,14,17-Eicosapentaenoic acid C20:5n3) ratio in a sample. The trait is EFO_0021753 (3-Indolepropionic acid to cis-5,8,11,14,17-Eicosapentaenoic acid C20:5n3) ratio).