If the biopsy shows that lymphoma cells are present, your doctor will want you to have some further tests to find out the exact stage of the lymphoma. Staging is a way of describing the extent and spread of the lymphoma in your body. It is very important because the type of treatment you have depends on the stage of the disease.

The tests that may be done to find the stage of your lymphoma may include any of the following:

Samples of your blood will be taken regularly throughout your treatment to check your general health, the levels of red cells, white cells and platelets in your blood, and how well your liver and kidneys are working.

This is taken to check for any sign that the lymphoma has spread to the lymph nodes in the chest or to the lungs.

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 from 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 is important to let your doctor know beforehand.

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

An MRI (magnetic resonance imaging) scan is similar to a CT scan, but uses magnetic fields instead of x-rays to build up a series of cross-sectional pictures of the body.

During the test you will be asked to lie very still on a couch inside a metal cylinder that is open at both ends. The whole test may take up to an hour and is painless – although the machine is very noisy. You will be given earplugs or headphones to wear.

The cylinder is a very powerful magnet, so before going into the room you should remove all metal belongings. You should also tell your doctor if you have ever worked with metal or in the metal industry or if you have any metal inside your body (for example, a cardiac monitor, pacemaker, surgical clips, or bone pins).  You may not be able to have an MRI because of the magnetic fields.

Some people are given an injection of dye into a vein in the arm, but this usually does not cause any discomfort. Some people feel claustrophobic inside the cylinder, but you may be able to take someone with you into the room to keep you company. It may also help to mention to the staff beforehand if you do not like enclosed spaces. They can then offer extra support during your test.

A small sample of bone marrow is usually taken from the back of your hipbone (pelvis). The sample is looked at under a microscope to see if it contains any lymphoma cells.

The bone marrow sample is taken under a local anaesthetic. You will be given a small injection to numb the area and the doctor will gently pass a needle through the skin into the bone. The doctor will draw a small sample of liquid marrow into a syringe to be looked at later under the microscope (bone marrow aspirate). The doctor will then take a small core of marrow from the bone (a trephine biopsy).

The test can be done on the ward or in the outpatients department. The whole procedure takes about 15–20 minutes. It may be uncomfortable as the marrow is drawn into the syringe but this should only last for a few seconds. You may be offered a short-acting sedative to reduce any pain or discomfort during the test.

You may feel bruised after the test and have an ache for a few days. This can be eased with mild painkillers.

This test is done on the ward or in the outpatient’s department. First, you will be given an injection of local anaesthetic. A thin needle is then put through the skin of your back into the fluid around your spine and a sample of spinal fluid will be taken. This will be examined in the laboratory to see if it contains any lymphoma cells. You will be asked to stay lying flat for at least an hour after the test, to reduce the chance of getting a headache.

Most people have no problems with this test, although when the needle is put in it can sometimes cause a tingling down the back of your legs. This is harmless, but can be worrying if you are not expecting it. Some people get a headache for a few days afterwards and may need to take painkillers.

PET (positron emission tomography) scans are a new type of scan so you may have to travel to a specialist centre to have one. They are not always necessary but you can discuss with your doctor whether one would be useful in your case. PET scans can be used to find whether a lymphoma has spread, or to examine any lumps that remain after treatment to see whether they are scar tissue or whether cancer cells are still present.

A PET scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. A scan is then taken a couple of hours later. Areas of cancer are usually more active than surrounding tissue and they show up on the scan.

It will probably take several days for the results of your tests to be ready and a follow-up appointment will be arranged for you to discuss them. Obviously this waiting period may be an anxious time for you and it may help you to talk things over with a close friend, relative or a support organisation. You can ask your doctor when your results will be available, so that you know how long you will have to wait.