D-3-hydroxybutyrate (HB) is a primary metabolite in diabetic ketoacidosis, alcoholism, or starvation. The untreated ketoacidosis can result in coma or death. The current tests for ketosis measure only acetoacetate (AA), which is a minor ketoacid and is unstable therefore, sometimes leads to error of diagnosis. Therefore, a simple, quick strip test for HB measurement will be a valuable tool for both diagnosis and management of ketosis. GDS Technology has recently developed a thermo stable D-3-hydroxybutyrate dehydrogenase (HBD) which will form the basis for a strip test (similar to Miles' or Boehringer's Glucose test) for the determination of HB. This proposal (Phase I) is a feasibility research which will focus on the development of a stable strip test by incorporating GDS' HBD enzyme and an indicator system which will produce color proportionate to the concentration of HB. The goal of Phase II will be to complete the development of the whole blood test and perform clinical studies. The program is attractive as it offers, for the first time, an opportunity for providing a simple and accurate test for ketosis or ketoacidosis that can be done on site, such as in physician's office, emergency rooms, or at home during insulin therapy.