Apparatus and methods are described including staining a blood sample with one or more stains. A plurality of microscopic images of the stained blood sample are acquired, using a microscope. Staining-quality parameters for respective microscopic images are determined, using a computer processor, the staining-quality parameters being indicative of a quality of the staining within each of the respective microscopic images. An action is performed by the computer processor, based upon the staining-quality parameters of the respective microscopic images. Other applications are also described.