A system for determining particle parameters. The system may, for example, may optically determine parameters common to a hematology analysis. Such parameters may include a red blood cell count, a platelet count, a mean cell volume and a red cell distribution width. A hematocrit parameter may be calculated. Also, a measurement of hemoglobin in a blood sample may be obtained leading to a calculation of a mean mass of hemoglobin in a red blood cell and a mean cell hemoglobin concentration. The system may be implemented in a portable cartridge type cytometer.