Red blood cells
Hemoglobin and red blood cells
Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body.
CBC blood test
Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called erythrocyte and RBC.