Blood tests in Follicular Lymphoma


For many people living with Follicular Lymphoma, periodic blood tests become a regular feature. There are several reasons you might need blood tests when affected by Follicular Lymphoma (FL), a form of non-Hodgkin’s lymphoma. But does lymphoma show up in blood work?

Generally, the answer is no, FL is rarely detected on standard or “routine” blood tests. Nonetheless, such blood tests do provide a great deal of information. 

Here’s what you need to know about Follicular Lymphoma and blood tests.

Can a blood test detect lymphoma?

A blood test will not be able to diagnose Follicular Lymphoma. If your doctor suspects lymphoma, you will need a scan and a lymph node biopsy to confirm it.  FL cells rarely circulate in the blood, at least in numbers that are detected by usual blood tests. More sensitive blood testing is being developed to find minimal (or measurable) residual disease remaining after treatment, but this is not a diagnostic test. Also, certain baseline blood tests may give some information, unfortunately not very precise, about how your FL might behave.

Blood work does, however, provide you and your medical specialist with an overview of your general health, and how it is being affected by the FL and its treatment. 

“Routine” blood tests have two main components:  one measures the numbers and types of all blood cells, called either a full blood count (FBC) or complete blood count (CBC); the other measures chemicals and proteins in the liquid part of the blood, called either urea and electrolytes (U&E) or blood chemistry panel (CMP). Together these tell how your bone marrow, where the blood is made, and your organs (mostly liver and kidneys) are functioning. More details on these are below.

Blood tests before treatment are helpful. If you are diagnosed with FL and have no symptoms, your doctor may consider “watch and wait”, meaning observation without treatment. However, even without symptoms, if your blood counts are low indicating the FL is interfering with bone marrow function, this might change the recommendation to begin treatment.  

If you are undergoing treatment, regular blood tests can also:

  • Show how your treatment is affecting your body and FL.
  • Check if you’ve recovered from one round or cycle of treatment before starting another.
  • Monitor your recovery.

After you have completed therapy, regular blood tests:

  • Check for signs of relapse or transformation of the FL.
  • Check for late effects (health problems including second cancers) that may develop following treatment.

What types of blood tests can you expect?

There are a few different blood tests you may undergo after a Follicular Lymphoma diagnosis.

Full blood count (FBC) or Complete blood count (CBC)

This measures your levels of red blood cells (haemoglobin and hematocrit are different but related measures of red cells), white blood cells and platelets. If blood cells are low due to FL cells in the bone marrow, the counts should improve as the FL responds to treatment. If the cells are low due to the treatment, there is an expected pattern of falling and then recovering prior to starting the next cycle of treatment. Low red cells, or anaemia, leads to tiredness and if more severed can cause shortness of breath and fast heart beat. Low platelets can allow bleeding. Low white cells, specifically the subtype called neutrophils (or granulocytes) that fight bacteria, are the ones of most concern as they can allow infections to be severe and fast-moving. You might require a white cell growth factor injection to prevent this. 

Blood film (or smear)

The FBC or CBC machine takes an automated look at the blood cells. For a more detailed inspection, a blood smear (also known as a peripheral blood smear) is reviewed under a microscope, either by your doctor or a special pathologist, to check for any cell abnormalities. This can be useful especially for looking at different types of white blood cells.

Blood chemistry (U&E, CMP)

These tests check your kidney and liver function, electrolytes (salts in the blood: sodium, potassium, calcium) and blood sugar.

Lactate dehydrogenase (LDH)

Lactate dehydrogenase (LDH) is an enzyme protein released when cells break down. It is not specific for lymphoma, or even for cancer, but if you have lymphoma, a high blood LDH may indicate that you have more lymphoma cells and they are dividing and breaking down faster. It is most common in FL, being low-grade or slow growing, to have normal LDH levels.  In FL, a rising high LDH raises concern for, but does not itself diagnose, more advanced disease or transformation to aggressive lymphoma. LDH can actually go up shortly after a treatment as the cells are killed, but then go back down.

Uric Acid

Uric acid, best known as the cause of gout, is also like LDH related to cells breaking down.  This is usually only a concern with faster growing lymphomas as treatment starts. Drugs can be used to prevent a dangerous rise in uric acid levels if that is a concern when a new treatment is starting.

Beta-2 microglobulin (B2M)

Some doctors recommend checking a baseline B2M level to help predict how indolent (if normal) or aggressive (if higher) your FL will behave. It is not generally useful to follow as an indicator of disease, however.

Antibody or immunoglobulin levels

Our antibodies, also called immunoglobulins (Ig) protect us against various infections. These are made by B cells, so B cell lymphoma patients, including those with FL, may have low Ig levels. Many FL treatments also kill normal B cells, so Ig levels may go down further. There are replacement Ig preparations available. Your doctor may periodically check Ig levels to see if they are low, discuss what you can do to reduce the risk of infection and possibly recommend replacement Ig.

Other blood tests

Depending on your circumstances, your specialist may carry out additional blood tests. For instance, a viral serology which checks for prior exposure to infections, such as HIV or Hepatitis B or C. These could be related to your lymphoma, and if there is a risk, they can flare up during treatment there are preventive treatments.

Support from the Follicular Lymphoma Foundation

FL is currently incurable. But incurable is not okay — at the Follicular Lymphoma Foundation (FLF), our mission is to lead new and determined efforts to find cures. If you’d like to learn more, please see our programmes.

As a leading Follicular Lymphoma charity, we’re also here to support those living with FL. Whether you’ve just been diagnosed, are facing relapse, or want to help a loved one with FL, our aim is to help Follicular Lymphoma patients live well and get well.

Please don’t hesitate to get in touch if you’d like to connect with our global online community.