Enzymatics, Inc. has developed an enzyme-based colorimetric technology that allows creation of quantitative, disposable, instrument-independent diagnostic devices for analytes in bodily fluids. The objectives of this grant are to complete development of a prototype device for determination of total blood cholesterol, and to evaluate the prototype. Specific research deals with refinements of factors influencing the speed, accuracy and precision of the device. Prototype evaluation will involve a limited clinical trial. Commercialization of the successful prototype will significantly lower the cost of routine cholesterol determination, increase rapidity of cholesterol determination and improve reliability of measurements.