Abstract: Color-based (colorimetric) breast milk analyses using test strips (paper-based assays) read with the smartphone camera to quantify the concentration in accordance with embodiments of the invention are disclosed. In one embodiment, a color-based strip for testing breast milk is provided, the strip including: a first portion including a protein reagent pad where exposing the protein reagent pad to breast milk results in a first reaction for measurement of total protein concentration in the breast milk, a second portion including a fat reagent pad where exposing the fat reagent pad to breast milk results in a second reaction for measurement of fat concentration in the breast milk, and a third portion that is or includes a lactose reagent pad where exposing the lactose reagent pad to breast milk results in a third reaction for measurement of lactose concentration in the breast milk.