Apparatus and methods are described for determining a property of a bodily sample using a microscope and optical-density-measurement apparatus, the apparatus including a sample carrier that includes a plurality of microscopy sample chambers configured to receive a first portion of the sample and to facilitate imaging of the first portion of the sample by the microscope, each of the microscopy sample chambers having an upper and a lower surface, and having respective heights between the upper and lower surfaces that are different from each other. The sample carrier includes at least one optical-density-measurement chamber configured to receive a second portion of the sample, and to facilitate optical density measurements being performed optical-density-measurement apparatus upon the second portion of the sample. Other applications are also described.