Abstract: A multifunctional device for measuring fluorescence, luminescence and light transmission for diagnostics comprises a first and second group of screens mounted behind the rear surface of a sample solid carrier. A sample carrier is designed in the form of a biochip, cell, pan or microplate. The sample carrier's light sources are provided with light-absorbing elements for suppressing light reflected from the front surface of the sample carrier and from screen surfaces. Screen holders allow for alternatively mounting light reflective/retroreflective screens to maximize fluorescent or luminescent signal. A diffusing screen measures light transmission through the sample. Light-absorbing screens behind the rear surface of the sample and light-absorbing elements on light sources from the sample's top surface, increase signal-to-noise ratio. The device permits measuring signals on biochip surfaces and in solutions during hybridization or amplification reactions.