A blood test is when a sample of blood is taken for testing in a laboratory. Blood tests have a wide range of uses and are one of the most common types of medical test. For example, a blood test can be used to:
- assess your general state of health
- confirm the presence of a bacterial or viral infection
- see how well certain organs, such as the liver and kidneys, are functioning
A blood test usually involves the phlebotomist or nurse taking a blood sample from a blood vessel in your arm. and the usual place for a sample is the inside of the elbow or wrist, where the veins are relatively close to the surface. Blood samples from children are taken from the back of the hand or the inside of the elbow. The child's hand will be anaesthetised (numbed) with a special cream before the sample is taken.
You can find out more about blood tests, their purpose and the way they are performed on the NHS Choices website.
If you think you need a blood test, but have not been instructed by the nurse or doctor to book one, then please see your doctor first, as they will need to authorise the test before it can be performed.