Color aspects of reagents used visually in clinical analysis

Reagent strips are clinical chemistry tests that are quick and convenient to use. Some require the user to compare the color of a test pad to that of a color chart to obtain an assay result. Quantitative color measurement has great value in the development and use of reagent strips. It permits an accurate assessment of the visual performance of the reagents. Reagents for urine specific gravity, hemoglobin, urobilinogen, and glucose are illustrative of the chemistries and colors of reagent strips. Quantitative visual measurements, computer formulated color charts, and the effects of the illuminant, observer, and background color are discussed.