Blood tests can help doctors assess your heart
health, by checking your risk for developing heart and circulatory
If you've already been diagnosed with a heart condition, blood
tests can help monitor your condition and the effects of your
medicines if you are taking any.
What is a blood test?
A blood test is when a sample of your blood is taken for testing in a
Your doctor or nurse may take your blood sample, or
sometimes a phlebotomist (someone who is specifically trained to
take blood samples) will carry out the test. You may have your
blood test at hospital or at your local GP
How is the blood taken?
For most blood tests, your blood will be taken through a
needle which is inserted through your skin into a
vein. The arm is usually used as it’s
easily accessible, and the common places to take blood are from
inside your elbow or the top of your
wrist, as your veins are closer to the surface
A tight band (tourniquet) is usually put
around your upper arm. This causes the vein to swell and fill with
blood making it easier for your blood sample to be taken. The area
may be cleaned with an antiseptic wipe or swab before the test is
The needle is usually attached to either a
syringe or a special blood collecting container, so once the blood
sample has been taken it can easily be sent to a laboratory for
A blood test usually only takes a
Does a blood test hurt?
You may feel a slight pricking sensation as the needle goes in,
but it should not be painful. You might also feel
a slight discomfort when the needle is taken out.
If you don’t like needles and
injections, let the person who is taking the sample know so
they can make you more comfortable. If you feel anxious about your
blood test, ask a family member or friend to go along with you.
Rarely, some people feel faint during a
blood test. Tell the person doing the test if you do feel faint as
you should immediately lie down.
What about afterwards?
Once the sample has been taken, you or your
health professional will apply pressure to the area with a dressing
to stop any bleeding and to prevent swelling and bruising.
You may still get a small bruise or
swelling where the needle went into your skin. If
this feels painful you should rest your arm as much as
possible and try putting ice on the area. If you are worried or the
pain is severe, speak to your doctor or nurse for more advice.
As only a small amount of your blood is
taken in a blood test, you should not feel ill
from loss of blood.
Different types of blood tests
The most common types of blood tests used
to assess heart conditions are:
- Cardiac enzyme tests
(including troponin tests) – which help show if
your heart muscle has been damaged
- Full blood count
(FBC) – which measures the different types of
blood cells in your blood and can show, for example, if there is an
infection in your bloodstream
- Thyroid function tests –
which show if you have an underactive or overactive thyroid, which
can be linked to heart palpitations or a very slow or fast heart
- BNP (B-type natriuretic peptides)
tests – which show the level of hormones in your blood
which can be a sign of heart
- U and Es test – this
stands for 'urea and electrolytes' and shows if there is too much
or too little sodium or potassium in your blood. These are
important for the overall function of your heart and also help
asses kidney function. Imbalances in the blood can be linked to
medication that you may be taking.