Liquid testing system, devices, and methods

A fluid assay testing device configured to test a sample of fluid from a fluid source for analyte levels, the device comprising:

• a fluid flow path to provide the sample of fluid to a test cartridge containing a filter membrane, and to provide a conjugate of analyte-specific binding reagents with labels to the test cartridge, wherein the conjugate collects on a filter membrane by specifically binding to a target analyte captured on the filter membrane of the test cartridge,
• wherein the fluid flow path includes a pump and a valve;
• a translational base to position a test cartridge for analysis;
• an excitation mechanism to excite the labels for optical analysis;
• and
• an optical detector to detect optical frequencies of the excited labels to determine a target analyte level.