Apparatuses, systems, and methods for sample testing

A sample testing device comprising:

• a waveguide cartridge comprising a waveguide, wherein the waveguide comprises at least one reference channel and at least one sample channel;
• a reference reservoir connected to the at least one reference channel;
• a sample reservoir connected to the at least one sample channel;
• a multiport valve connected to an inlet of the waveguide cartridge and configured to provide a plurality of configurations comprising:
• a first configuration connecting the inlet of the waveguide cartridge to an outlet of the waveguide cartridge,
• a second configuration connecting the inlet of the waveguide cartridge to the at least one reference channel and the at least one sample channel, and
• a third configuration connecting the inlet of the waveguide cartridge to each of the reference reservoir and the sample reservoir;
• and
• an imaging component coupled the waveguide and configured to capture interference fringe patterns from the waveguide, wherein the multiport valve is switched to the second configuration from the third configuration based on the interference fringe patterns captured by the imaging component.