If you see your GP because you're concerned about symptoms of non-Hodgkin lymphoma, they'll ask about your health and may carry out a simple physical examination.
If necessary, your GP will refer you to hospital for further tests.
If you're referred to hospital, a biopsy will usually be carried out, as this is the only way to confirm a diagnosis of non-Hodgkin lymphoma.
A biopsy involves removing some or all of the swollen lymph node, which is then studied in a laboratory.
A biopsy is a small procedure or operation that can often be carried out under a local anaesthetic (where the area is numbed, but you're awake).
This may be performed by a radiologist using an ultrasound or CT scan, or as an operation by a surgeon.
In some cases, the swollen lymph node isn't easily accessible and a general anaesthetic may be required (where you're asleep).
A pathologist (an expert in the study of diseased tissue) 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 important for planning your treatment.
There are more than 30 types of non-Hodgkin lymphoma.
The Macmillan Cancer Support website has detailed information on the different types of non-Hodgkin lymphoma.
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.
Further tests may include:
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's 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.
Read more about preparing for and understanding your cancer test results.
Testing can also help health professionals decide the "grade" of the cancer.
There are 2 main grades of non-Hodgkin lymphoma:
Low-grade tumours don't necessarily need immediate medical treatment, but are sometimes 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.