A blood test is when a small sample of blood is taken and sent for laboratory testing. The blood is taken by a trained professional, usually a nurse or phlebotomist. Blood tests have a variety of uses and are probably the most common type of medical test that people will have. Blood tests can be used to look for specific genetic diseases, such as cystic Fibrosis for example, or they can be used to check a person’s general state of health. They can also show the presence of viruses or a bacterial infection and can show how well certain organs such as the liver or kidneys are working. This means that blood tests are often the first tests that a patient will be given when they visit their doctor with concerns about a symptom or set of symptoms. However, some conditions are not apparent until they have entered quite a serious phase and by the time symptoms become apparent damage may already have been done to a person’s body. It is for this reason that people who have a family history of a certain disease, such as heart disease or some types of cancer may request a blood test without experiencing any symptoms so they can check whether they have cause for concern.
A blood test can also be helpful in preventing disease. This is because they can check the function of some organs such as the kidneys and so a patient could find out from a simple blood test that their kidneys weren’t functioning as well as they might and so they could take steps to change their lifestyle (eg lower alcohol consumption) and so reduce the risk of developing kidney disease in the future. Blood tests can also measure the levels of certain hormones or other substances in the blood. One common test is to check the levels of both HDL and LDL cholesterol. High LDL cholesterol levels can lead to narrowing of the arteries and therefore heart attack or stroke, so by finding out if a patients level is higher than the recommended level it may be possible to avoid serious illness with medication or simply lifestyle change.
A blood test is usually quick and easy to perform and is rarely painful, although the needle used is sharp so a slight prick may be felt. Once the needle is removed a cotton wool pad is placed on the wound to apply pressure, which helps prevent bruising in that area. Only a small amount of blood is taken and side effects are unusual, although some people can feel slightly dizzy afterwards for a brief time.
By taking this quick, easy and relatively painless test a patient can find out a lot of extremely useful information that could allow them to make positive changes to their lifestyle and lower their chances of developing serious and even fatal diseases. Even if the blood test shows the patient to be in perfect health it will have provided reassurance, although future testing may also be advisable.