Hemoglobin (Hb) is a protein found in red blood cells that carries oxygen from the lungs to all the tissues and organs in the body. A hemoglobin test measures the amount of hemoglobin in your blood, which is expressed in grams per deciliter (g/dl). The normal Hb level for males is 14 to 18 g/dl, and for females, it is 12 to 16 g/dl. If a hemoglobin test reveals that your hemoglobin level is lower than normal, it means you have a low red blood cell count (anemia). Anemia can have many different causes, including vitamin deficiencies, bleeding, and chronic diseases. If a hemoglobin test shows a higher than normal level, there are several potential causes, including the blood disorder polycythemia vera, living at a high altitude, smoking, and dehydration.
In summary, hemoglobin is a protein in red blood cells that carries oxygen throughout the body, and a hemoglobin test measures the amount of hemoglobin in the blood. A low hemoglobin level may indicate anemia, while a high level may indicate polycythemia vera, living at a high altitude, smoking, or dehydration.
