A hydrophobic coating for plastics was designed to compliment the company’s proprietary diagnostic adhesive, GL-187. The coating can be successfully applied to polyester, polystyrene, vinyl, and other plastics for IVD and a variety of other medical applications. The hydrophobic treatment makes water and most other liquids bead up on the surface, similar to a newly waxed car. The coating is capable of producing extremely high contact angles in an ideal application environment. This treatment is especially useful in dry chemistry applications such as multi-parameter water and urine tests to reduce cross contamination thereby supporting more accurate test readings.