Devices and methods for performing a point of care diagnostic test for detecting and quantifying at least one analyte in a biological sample. The device may include an immunoassay apparatus and a holder with a variable angle stage for positioning the immunoassay apparatus relative to a light source and a detector device. In one embodiment, the device is based upon elastic light scattering, so the variation in the angle of incidence and angle of reflection are optimized to maximize signal generation due to elastic light scattering. The detector device may include a wired or wireless connection to a computer network for communicating with an electronic medical records system, uploading the amount or concentration of at least one analyte present in the sample to the electronic medical records system, or querying a decision support algorithm stored in a computer readable format. The detector device may further include an onboard interpretive algorithm.