Hematocrit is the percentage by volume of red cells in your blood. Blood is made up of red blood cells, white blood cells and platelets, suspended in plasma. Together, those comprise about 45% of the volume of our blood, but the specific percentages of each can vary.
Hematocrit level is simply the percentage of red cells in your blood. For example, a level of 38% is considered the minimum needed for donating blood.
Normal hematocrit levels vary based on age and race.. In adults, normal levels for men range from 41%-50%. For women, the normal range is slightly lower: 36%-44%. A hematocrit level below the normal range, meaning the person has too few red blood cells, is called anemia. A hematocrit level above the normal range, meaning too many red blood cells, may indicate polycythemia or erythrocytosis.
Your doctor may test your hematocrit levels if you show signs of having anemia, polycythemia or erythrocytosis. Symptoms of anemia include fatigue, shortness of breath and dizziness. Symptoms of polycythemia include fatigue, itching, headaches, and sweating. Symptoms of erythrocytosis includes headaches, dizziness, shortness of breath, and nosebleeds.
Hematocrit and hemoglobin measurements are both blood tests but they are not testing the same thing.
Hemoglobin is checked before each blood donation. This is to ensure that the donor has adequate red blood cell levels to donate blood. Blood donors must have a minimum of 12.5 g/dL hemoglobin but no greater than 20 g/dL. (There are separate requirements for the red cell-only donation known as Power Red.)
Recent studies show that there is a need for blood transfusions every 2 seconds. Blood donations can help trauma patients, cancer patients, people with chronic illnesses, and more. 38% of the population in the United States are eligible to donate blood, but only 3% of us actually donate.
