Abstract: Methods and apparatus for generating a code-multiplexed readout value of photocurrents for a photo-detector array of cells are disclosed. Readout values are determined using a multiplexer and current amplifier for each cell and a current-to-voltage converter for each row of cells. The multiplexer multiplexes a photocurrent in an electrical domain for a respective cell using a code and generates electric currents responsive to the photocurrent. The current amplifier amplifies the electric currents. The current-to-voltage converter for each row generates the readout value for that row of the array responsive to the amplified electric currents.

Abstract: A method of detecting the presence of selected microorganisms within a fluid includes filtering the fluid to remove large particles prior to analyzing the fluid with an antibody matrix. Non-specific binding is eliminated by washing and the presence of biological material is detected. If biological material is detected within the matrix, specific secondary antibodies are added which confirm the presence of the microorganism of interest and are also used to quantitate the level of the microorganism within the sample.