Abstract: A diagnostic test device to perform a test on a biological or environmental sample is provided. In one aspect, the diagnostic test device includes a chamber configured to receive a fluid from a sample preparation reservoir at a first section of the chamber, and a plurality of spaced apart valleys along an inner surface of the at least one chamber. Each of the plurality of spaced apart valleys include a curved cross-section and is configured to promote flow of the fluid toward a second section of the at least one chamber.

Abstract: A diagnostic test device to perform a test on a biological or environmental sample is provided. In one aspect, the diagnostic test device includes a chamber configured to receive a fluid from a sample preparation reservoir at a first section of the chamber, and one or more capillary grooves along an inner surface of the chamber. The capillary grooves are configured to promote flow of the fluid toward a second section of the chamber. Embodiments of the diagnostic test reservoir can increase an amount of sample available to an assay reaction, which in one example embodiment occurs within a volume of fluid in the second section of the chamber.