Hemolymph from the American lobster (Homarus americanus) was analyzed by optical spectroscopy for the concentration of total hemolymph proteins and results were compared with a more traditional technique: refractometry. Absorbance peaks at 280 nm for total hemolymph protein concentration and 334 nm for hemocyanin concentration were studied, compared with equivalent refractometry readings, and correlated to the vitality of the lobster. These spectroscopic measurements constitute engineering data in the design a future noninvasive, field-deployable microinstrument to sort lobster according to their health and long-term viability.