WHAT IS A BLOOD TEST?
Blood is made up of different cells and other compounds. These include proteins and various salts. If your blood becomes infected by organisms, you can become ill. A blood test is a very useful tool that enables a doctor to check for harmful organisms in your blood. Blood consists of two main elements. The liquid part is called plasma and the other elements are the cells. Doctors perform several tests with blood samples to get the information they need. These include a blood smear test and measurement levels of the cells. In a blood smear, blood is placed on a slide so that doctors can look at the blood under a microscope. They can see the cells up close and check for harmful organisms. A blood sample for a blood test can be taken from either an artery or a vein. In the most common type of blood test, blood is taken from a vein. If the blood sample needed is very small, then a prick to the tip of a finger will allow enough blood to be taken.
Blood tests help a physician to diagnose and manage a disease. In addition to examining blood cells, there are many chemicals in the blood that give important information about the functioning of bodily systems. Important chemicals that may be measured include cholesterol, thyroid hormone, potassium, and numerous others. These various chemicals are dissolved in the plasma and circulate in the blood. For a chemical blood test, blood is drawn from a patient’s vein and placed in an empty tube and usually allowed to clot; the fluid portion of the blood after clotting, called serum, is then used for the various chemical analyses.
A blood test uses a sample of blood from a vein a process called venipuncture to detect and measure various factors in the blood. Blood is normally taken from a vein in the arm and afterwards a small plaster is used if necessary to stop the bleeding. The precise amount of blood taken is determined by the type and number of tests to be undertaken.
