A system for separating bodily fluid constituents is disclosed. The system includes a first substrate which, in a first main surface, has a first cavity for holding a bodily fluid sample, a second substrate, which, in a first main surface facing the first substrate, has a second cavity) for holding constituents separated from the bodily fluid sample, which second cavity lies opposite to the first cavity, a filter layer, which is arranged between the first substrate and the second substrate and which is designed to separate constituents of the bodily fluid sample in the first cavity and to pass the separated constituents to the second cavity, and a first thermoplastic connection layer, which is arranged between the first substrate and the filter layer, interconnects the first main surface of the first substrate and the filter layer in a fluid-tight manner and has a cutout lying opposite to the first cavity.
