Abstract: The method of analyzing samples (3) in the wells (2) of a microplate (1) comprises the steps of producing electromagnetic radiation having a first predetermined wavelength or wavelength range (101), illuminating a sample (3) by said radiation by transmitting the radiation to the sample (3) from above the microplate (1) via the upper end of the well (102), transmitting light emitted by the sample (3) and having a second predetermined wavelength or wavelength range via the upper end of the well (2) to detection means (13) (103), determining intensity of light emitted by one or more predetermined measurement areas (23) of the sample (3) (104), based on the determined intensities, determining a result value representing the total amount of light emitted by the sample (3), and counting the number of spots emitting light having the second predetermined wavelength or wave-length range (106).

Abstract: The optical reader for analyzing biological samples comprises a reading plane (3) for receiving a microplate (1), an illuminating arrangement (4) configured to illuminate samples in the wells (2) of the microplate (1), an imaging device (6) arranged to receive light from the microplate (1), a beam splitter (7), which is arranged to direct light from the illuminating arrangement (4) towards the reading plane (3) and to direct light received from the microplate (1) to the imaging device (6), and a lens system (8) arranged between the beam splitter (7) and the reading plane (3) to focus the light received from the illuminating arrangement (4) to a sample and to focus an image of the sample to the imaging device (6).