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 taking a blood sample from a blood vessel in your arm. and the usual place for a sample is the inside of the elbow where the veins are relatively close to the surface.
Very young children may be referred to the paediatric unit at Musgrove Park Hospital for blood tests, although the nurses here can take samples from children. The child will be prescribed a local anaesthetic cream which should be applied to the inside of both elbows at least 30 minutes prior to their appointment.
You can find out more about blood tests, their purpose and the way they are performed on the NHS Choices website.