Gasket sealability test techniques are used to characterize gasket material properties as they relate to sealing performance. Increasing use of coated metal gasket materials with formed sealing features extends this test method to also characterize the influence of gasket design features known as embosses or beads. The essence of gasket sealability test methods involves compressing the gasket specimen between flat and presumably parallel surfaces of the test platens. This paper explores the effects of platen parallelism on sealability test results. Initial investigations have revealed platen parallelism has a significant effect on observed test results with certain gasket materials. The primary focus of this work involves rigidly mounted platens as opposed to spherically mounted, or wobble platens. Techniques for evaluating the rotational bending stiffness of platen and loading fixture configurations are also presented.