Navnihaal manual blood cell counter, often referred to as a hemocytometer or a counting chamber, is a laboratory instrument used to manually count and quantify the number of blood cells, such as red blood cells (RBCs) and white blood cells (WBCs), in a blood sample. This device is primarily employed in clinical laboratories, research settings, and medical facilities to assess the concentration of blood cells, which can be crucial in diagnosing various medical conditions and monitoring a patient's health.