Most people begin by seeing their GP when they develop symptoms. Your GP will examine you and arrange for you to have tests or x-rays. Your GP may need to refer you to the hospital for these tests, and for specialist advice and treatment.

At the hospital, the specialist will ask you about your general health and any previous medical problems before examining you. A chest x-ray will be taken to check for any abnormalities in your lungs. You may also be asked to give samples of phlegm (sputum), so that they can be examined under a microscope for cancer cells – this is known as sputum cytology.

The following tests may be used to diagnose cancer of the lung. Your doctor may arrange for you to have one or more of them.

A CT (computerised tomography) scan takes a series of x-rays which build up a three-dimensional picture of the inside of the body. The scan is painless but takes 10 to 30 minutes. CT scans use a small amount of radiation, which will be very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.

You may be given a drink or injection of a dye which allows particular areas to be seen more clearly. For a few minutes this may make you feel hot all over. If you are allergic to iodine or have asthma you could have a more serious reaction to the injection, so it’s important to let your doctor know beforehand.

You will probably be able to go home as soon as the scan is over.

Some hospitals use low-dose spiral CT scans (helical CT scans). A CT scanning machine rotates rapidly around the body, taking more than one hundred pictures in sequence. The scan can detect smaller lung tumours than a conventional CT scan and takes only a few minutes. Spiral CT scans are quite new and you may have to travel to a specialist hospital to have one. They are not always necessary, but you can discuss with your doctor whether one would be useful in your case.

A doctor, or a specially trained nurse, examines the inside of the lung airways and takes samples (biopsies) of the cells. Normally a thin, flexible tube called a bronchoscope is used and the test is carried out under local anaesthetic. Sometimes a rigid bronchoscope is used instead. In this case, a general anaesthetic is given and you may have to stay in hospital overnight. A CT scan will tell the doctors whether a bronchoscopy will be helpful. It will also guide the doctor or nurse to the abnormal area in the lung.

Before your bronchoscopy, you will be asked not to eat or drink anything for a few hours. Just before the test you may be given a mild sedative, to help you relax and to relieve any discomfort. You will be given another medicine which reduces the production of natural fluids in the mouth and throat. This medicine can make your mouth feel dry.

Once you are comfortable, a local anaesthetic will be sprayed onto the back of your throat, making it numb. The bronchoscope is then gently passed into your nose or mouth and down into the lung airways. The doctor or nurse can look through the bronchoscope to check for any abnormalities. Photographs and biopsies can be taken at the same time.

The test may be slightly uncomfortable, but it only takes a few minutes. You shouldn’t eat or drink for at least an hour afterwards, because your throat will be numb and you won’t know if food and drink is going down the wrong way. As soon as the sedation has worn off you will be able to go home. You shouldn’t drive for 24 hours after the test as you may feel sleepy, so you'll need to arrange for someone to collect you from hospital. You may have a sore throat for a couple of days after your test, but this will soon disappear.