Blood tests

Taking blood sample

There are a wide number of blood tests used to evaluate different types of lung conditions. They can help to diagnose lung conditions, monitor the impact that lung diseases have on health or monitor the response to treatment.

Arterial Blood gas (ABG):

  • An ABG is a sample of blood taken from an artery with a needle.
    • Usually the radial artery at the wrist.
  • It measures the levels of oxygen and carbon dioxide in the blood.
  • Some lung diseases can cause low oxygen levels (hypoxia) and some can cause the carbon dioxide levels to be high (hypercapnia).
  • Hypoxia and hypercapnia can be dangerous and need treatment.

Full Blood Count (FBC)

A Full Blood Count looks at red and white blood cells.

  • The number of red blood cells may be higher if oxygen levels are chronically low to maximise the oxygen carrying capacity of the blood.
  • If red cells are low (in anaemia) this might make the person feel breathless.
  • If there is an infection white blood cell numbers may be higher as they are used to fight off the infection.
  • If the person has recurrent infections then there may be a problem with the white cells and numbers may be low.
  • Some treatments suppress the immune system. A FBC can be used to monitor the side effects.