Hemoglobin is primarily used in medical and diagnostic applications. It plays a crucial role in oxygen transport within the blood, making it essential for treating conditions like anemia and blood loss. In healthcare, hemoglobin levels are measured to assess overall health and diagnose disorders such as sickle cell anemia or thalassemia. Additionally, hemoglobin-based oxygen carriers (HBOCs) are being developed as blood substitutes for use in emergencies when donor blood is unavailable. In research, hemoglobin is studied to understand oxygen metabolism and to develop treatments for blood-related diseases. Its unique properties also make it a subject of interest in bioengineering and artificial blood development.