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. If the blood is taken from an artery or vein, then a needle is used. It is usually quite painless with only a small amount of discomfort.

A blood test allows the doctor to look at the different type of cells in the blood. Red blood cell tests are the most important. The red blood cell test finds out how much hemoglobin there is in the body. Haemoglobin is vital as it carries oxygen around the body. If a person is suffering from anemia, then their hemoglobin count will be lower than normal.

The second blood test is the white blood cell test. The doctor needs to work out how many different types of white blood cells a patient has. Due to bacterial infection, the level of white blood cells may vary. When a person has autoimmune problems, in which the antibodies that should fight diseases attack the body instead, the white cell count may be low. Viral infections can also be a cause of low white blood cell count.

Another blood test is testing the platelet level. Platelets are small cells that coagulate when you have an injury. They form the basis of a blood clot to stop blood from flowing if you cut yourself. If you have low platelet levels, you can be vulnerable to excess bleeding. If the blood test shows a higher than normal level of platelets, you may be more vulnerable to excessive clotting.

Another blood test can be conducted to determine if the patient is suffering from coagulation disorders. A coagulation problem means that blood either doesn't clot properly or clots too well. Coagulation problems can sometimes be hereditary or may be due to liver problems. Blood tests are a very helpful and commonly used procedure. They enables the doctor to make a more specific diagnosis of a patient's illness.