A test sensor assisting in determining an analyte concentration in a fluid sample comprises a lid, a base and a spacer. The spacer has first and second spacer sections. The first spacer section has a first spacer side and a first spacer end. The second spacer section has a second spacer side and a second spacer end. The lid, base and spacer are attached such that a fluid chamber is formed between a portion of a lower lid surface and an upper base surface, and between the first and second spacer sides. The lower lid surface, the upper base surface, the first spacer end and the second spacer end form a side vent therebetween that is in communication with the fluid chamber.