The HGB test, also known as a hemoglobin test, is a blood test that measures the amount of hemoglobin in a person's blood. Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. The test is used to detect anemia, a condition in which there is a lack of oxygen in the body due to a low number of red blood cells or a low amount of hemoglobin in the red blood cells. It can also be used to monitor the effectiveness of treatment for anemia and to check for bleeding or other conditions that may cause a decrease in the amount of hemoglobin in the blood. Hemoglobin is a protein found in red blood cells that gives them their red color and helps to transport oxygen throughout the body. The HGB test measures the amount of hemoglobin in a person's blood in order to determine whether they have anemia, a condition in which there is a lack of oxygen in the body due to a low number of red blood cells or a low amount of hemoglobin in the red blood cells. Anemia can h...