Tests for diffuse large B-cell lymphoma (DLBCL)
This page is about tests for diagnosing and monitoring DLBCL. It is also relevant for people with other types of high grade non-Hodgkin lymphoma.
What you need to know
- You will need a range of tests to confirm a diagnosis of DLBCL.
- Tests are also used to work out the stage of the DLBCL, which helps with treatment decisions.
- Other tests are needed to check your overall health before you start treatment.
Lymph node biopsy
The main test for diagnosing DLBCL is a lymph node biopsy. This involves taking a sample from a lymph node (gland).
You will have one of these types of lymph node biopsy:
Incision or needle biopsy
You may have a small piece of tissue taken from the lymph node using a needle. This is usually done under local anaesthetic to numb the area.
You will normally have this biopsy as an outpatient, so you won’t need to stay in hospital afterwards.
Excision biopsy
You may have the whole lymph node removed (an excision biopsy). You will either have a local anaesthetic to numb the area, or a general anaesthetic so you sleep though the operation.
You may need to stay in hospital for the day. The doctor will make a cut to remove the lymph node so you will need a few stitches. Your hospital team will tell you how to look after the wound at home.
The lymph node sample is then sent away to a lab. A doctor will look for abnormal cells (lymphoma cells) under a microscope. They may also test the sample to find out more about the specific type of lymphoma you have.
You should get the results of the biopsy in around two weeks.
Genetic tests
Doctors may use your lymph node sample to look at changes in the genes of the lymphoma cells. Knowing about these changes can help them diagnose the specific type of lymphoma and decide on the best treatment.
For example, if you have changes in two particular genes, your diagnosis may be double hit lymphoma rather than DLBCL.
Genetic tests will also tell doctors more about your prognosis (what is likely to happen in the future).
You may hear your hospital team talk about FISH tests or molecular tests. These are just different ways to do genetic testing.
We have more information about genetic tests.
"Once I’d got home, it did start to hit me that I had a cancer diagnosis. But when you have a blood cancer that needs treatment straight away, you don’t have time to process what’s happening."
Jacqueline, diagnosed with DLBCL in 2017
Read Jacqueline's story about how she reacted to the shock of her diagnosis.
Staging tests
Staging describes how much of the body is affected by the lymphoma. It’s important because it helps your hospital team plan your treatment. Your doctor or nurse will explain your stage, and what this means for you.
Read our page about staging lymphoma.
PET-CT scan
The main staging test is a PET-CT scan. You will have an injection of a small amount of radioactive liquid called a tracer. The tracer shows up areas of the body where cells are more active. These are the lymphoma cells.
We have more information about PET-CT scans.
MRI scan
As well as a PET-CT scan, you may have an MRI scan. This checks whether there are any lymphoma cells in your central nervous system (CNS), which includes the brain and spinal cord. This is called CNS involvement.
If you have CNS involvement, you will have specific treatment for this.
Lumbar puncture
A lumbar puncture is occasionally needed to check for CNS involvement. It involves a needle being inserted into your spinal cord to draw out some fluid for testing.
Bone marrow biopsy
Bone marrow is the spongy material inside some of you bones where blood cells are made.
Rarely, you may have a bone marrow biopsy. This takes a sample of your bone marrow for testing.
Most people who have a PET-CT scan to stage the lymphoma won’t need a bone marrow biopsy. They are sometimes done if your team needs to check whether there is lymphoma in your bone marrow.
Blood tests
You’ll have blood tests to check how well your body is likely to cope with treatment.
You will have a full blood count (FBC) to measure the number of each type of cell in your blood: red blood cells, white blood cells and platelets. Your doctor may also request a blood film to look for abnormal cells.
You’ll have blood tests to check how well organs like your liver and kidneys are working. It’s important to know this before you start treatment as it may affect the level of drugs you are given.
You will be tested for viruses like hepatitis B, C and HIV, which might affect your treatment.
Other blood tests will check the level of antibodies in your blood, the health of your bones and how active the lymphoma is.
Other tests
You may have tests to check how well your heart and lungs are functioning, especially if you have a history of heart or lung disease.
Tests to monitor treatment
To monitor how your treatment is going, your hospital team will repeat some blood tests regularly. These include a full blood count (FBC), antibody tests, and tests to check how well your liver and kidneys are functioning.
You are likely to have a PET-CT or standard CT scan after treatment. . You may also have a scan during treatment if your hospital team thinks it’s needed.
If you are being treated for lymphoma cells in your spine or brain (your central nervous system), you may also need MRI scans. See staging tests.