The invention is an electronically processed single-step test device for detecting the presence of a preselected analyte in a fluid. The device includes a hollow rectangular outer casing, disposed within co-joined upper and lower sections of the casing are assay material, an electronic processing system, and a LCD display. The LCD display is observable through a viewing window. The assay material is a sorptive material including a fluid sample application region in the form of a sample wick in fluid communication with a test strip. The test strip includes an analyte capture region adjacent to a light shield. The electronic processing system includes red and green LEDs which are alternately pulsed or energized over predetermined periods of time to determine if fluid test results show a marker or markers in the capture region indicative of the presence of a preselected analyte in the fluid. If so, Yes+ is displayed on the LCD. If not, No− is displayed on the LCD.