Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts, and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets.Red blood cells (RBC) deliver oxygen from your lungs to your tissues and organs. White blood cells (WBC) fight infection and are part of your body's
defense system. Platelets help blood to clot when you have a cut or wound. Bone marrow, the spongy material inside your bones, makes new blood cells. Blood cells constantly die and your body makes new ones. Red blood cells live about 120 days, and platelets live about 6 days. Some white blood cells live less than a day, but others live much longer.
Blood tests show whether the levels of substances in your blood are within a normal range. They help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working. Some common blood tests measure
- The number, size, and shape of cells and platelets
- A differential - the number of different types of white blood cells
- Hemoglobin - an iron-rich protein in red blood cells that carries oxygen
- Hematocrit - how much space red blood cells take up in your blood
Problems with your blood may include bleeding disorders, excessive clotting and platelet disorders. If you lose too much blood, you may need a transfusion.
