If you see your GP with symptoms of non-Hodgkin lymphoma, they will ask about your health and carry out a simple physical examination.

If necessary, your GP will refer you to hospital for further tests. In hospital, it is likely that a biopsy will be carried out, as this is the only way to confirm a diagnosis of non-Hodgkin lymphoma.

Biopsy

A biopsy involves removing some or all of an affected lymph node, which is then studied in a laboratory.

Biopsies are small operations that can often be carried out under a local anaesthetic, although there may be some cases where the affected lymph node is not easily accessible and a general anaesthetic may be required.

A pathologist will then check the tissue sample for the presence of cancerous cells. If they find cancerous cells, they can also identify exactly which type of non-Hodgkin lymphoma you have, which is an important factor in planning your treatment.

Types of non-Hodgkin lymphoma

There are more than 30 types of non-Hodgkin lymphoma, including:

• diffuse large B-cell lymphoma
• follicular lymphoma
• extranodal marginal zone B-cell (MALT)
• mantle cell lymphoma
• Burkitt lymphoma
• mediastinal large B-cell lymphoma
• nodal marginal zone B-cell lymphoma
• small lymphocytic lymphoma
• lymphoplasmacytic lymphoma 
• peripheral T-cell lymphoma
• skin (cutaneous) lymphomas
• anaplastic large-cell lymphoma
• lymphoblastic lymphoma

The Macmillan Cancer Support website has more detailed information on the different types of non-Hodgkin lymphoma.

Further testing

If a biopsy confirms a diagnosis of non-Hodgkin lymphoma, further testing will be required to check how far the lymphoma has spread. This allows a doctor to diagnose the stage of your lymphoma (see below).

Further tests may include:

• Blood tests – samples of blood will be taken throughout your diagnosis and treatment to check your general health, the levels of red and white cells and platelets in your blood, and how well organs, such as your liver and kidney, are working.
• Bone marrow sample – another biopsy may be carried out to see if the lymphoma has spread to your bone marrow. This involves using a long needle to remove a sample of bone marrow from your pelvis and can be done using a local anaesthetic.
• Chest X-ray – can check whether your lymphoma has spread to your chest or lungs.
• Computerised tomography (CT) scan – takes a series of X-rays that build up a three-dimensional picture of the inside of the body to check the spread of your lymphoma.
• Magnetic resonance imaging (MRI) scan – uses strong magnetic fields to build up a detailed picture of areas of your body to check the spread of your lymphoma.
• Positron emission tomography (PET) scan – a type of scan that measures the activity of cells in different parts of the body. It is usually taken at the same time as a CT scan to show precisely how the tissues of different sites of the body are working. It can check the spread of the cancer and the impact of treatment.
• Lumbar puncture – using a thin needle, a sample of spinal fluid is taken and examined to see if it contains any lymphoma cells.

Staging non-Hodgkin lymphoma

When the testing is complete, it should be possible to determine the stage of your lymphoma. Staging means scoring the cancer by how far it has spread.

The main stages of non-Hodgkin lymphoma are.

Health professionals also add the letter 'A' or 'B' to your stage to indicate whether or not you have certain symptoms.

'A' is put after your stage if you have no additional symptoms other than swollen lymph nodes. 'B' is put after your stage if you have additional symptoms of weight loss, fever or night sweats.

In some cases, health professionals also use additional letters to indicate where the cancer first developed. For example, 'E' (extranodal) means the cancer developed outside the lymphatic system.

Grading non-Hodgkin lymphoma

Testing can also help health professionals decide the 'grade' of the cancer. There are two main grades of non-Hodgkin lymphoma:

• low-grade or indolent non-Hodgkin lymphoma is where the cancer develops slowly, and you may not experience any symptoms for many years
• high-grade or aggressive non-Hodgkin lymphoma is where the cancer develops quickly and aggressively

Low-grade tumours do not necessarily require immediate medical treatment, but are harder to completely cure. High-grade lymphomas need to be treated immediately but tend to respond much better to treatment and can often be cured.

In some cases, low-grade lymphomas can develop into high-grade lymphomas over time.

Read more about treating non-Hodgkin lymphoma.