What is a blood test?
A small sample of your blood is taken for testing to assess your health. This may be to monitor an ongoing condition, to confirm the presence of a bacterial or viral infection, to see how well certain organs are functioning, to check your blood count or vitamin levels, and so forth.
Most blood tests only take a few minutes.
Typically, a tourniquet is applied to the arm, then a needle attached to a syringe is gently inserted into one of the veins on the inside of your elbow or wrist – you will feel a sharp prick.
A sample of blood is taken and the needle is removed. You will be given a cotton-wool pad to press on the site, which stops further bleeding and should prevent bruising (though bruises sometimes do happen).
The results can help detect health problems in early stages, when treatments or lifestyle changes
may work best.