An improved electronic diagnostic device for detecting the presence of an analyte in a fluid sample comprises a casing having a display, a test strip mounted in the casing, a processor mounted in the casing, and a first sensor mounted in the casing and operatively coupled to the processor. The processor is configured to receive a signal from the first sensor when the device is exposed to ambient light thereby causing the device to become activated. The device includes a light shield that exerts pressure across a width of the test strip to prevent fluid channeling along the length of the test strip. The processor is configured to present an early positive test result reading when a measured value exceeds a predetermined early reading threshold value at any time after a predetermined early testing time period.