Lymph Node Biopsy
Diagnosing non-Hodgkin lymphoma (NHL) usually involves performing a lymph node biopsy. If the biopsy confirms that you have the disease, your doctor performs additional tests to stage the lymphoma.
A lymph node biopsy's purpose is to confirm a diagnosis and:
- identify your NHL subtype
- develop a treatment plan
Lab Tests to Confirm a Diagnosis
After your doctor takes samples of your lymph node and tissues, a hematopathologist examines them under a microscope to look for identifying characteristics of NHL. He or she confirms a diagnosis and identifies the NHL subtype. A hematopathologist is a specialist who studies blood cell diseases by looking at samples of blood and bone marrow cells and other tissues.
The hematopathologist uses one or more lab tests such as those below to examine your cells:
- Immunophenotyping confirms an NHL diagnosis and identifies the lymphoma cells as B cells, T cells or natural killer cells.
- Cytogenetic analysis looks for changes in chromosomes. The abnormalities help identify the NHL subtype.
- Gene expression profiling and microarray analysis identify the subtype and risk factors. They help predict treatment response and identify patients who may be at increased risk for relapse.
- Polymerase chain reaction (PCR) analyzes certain genes to help predict treatment response. This test is also used to detect residual lymphoma cells too small to be seen under a microscope.
Since NHL is a difficult disease to diagnose, you may want to get a second medical opinion by an experienced hematopathologist before you begin treatment. Some types of NHL can be confused with each other. The appropriate treatment depends on having the correct diagnosis.
Once your doctor confirms an NHL diagnosis, he or she runs more tests to stage your disease. Staging identifies the extent of your disease and where it's located in your body.
Staging tests include:
- a physical exam
- imaging tests
- blood tests
- bone marrow tests
Your doctor conducts one or more imaging tests (also called diagnostic radiology), along with a physical exam, to look for:
- the location and distribution of enlarged lymph nodes
- the effects of the disease, if any, on other organs such as the lungs or liver
- large tumor masses
Imaging tests may include:
- an X-ray
- a computed tomography (CT) scan of the neck, chest, pelvis and abdomen (stomach area)
- a magnetic resonance imaging (MRI) scan
- a positron emission tomography (PET) scan
- a fluorodeoxyglucose PET (FDG-PET) scan of the entire body with a radioactive tracer (F-18)
After your blood is taken, it's sent to a lab for a complete blood count (CBC) and more blood work. Your blood is measured for:
- levels of red cells, white cells and platelets
- the presence of lymphoma cells
- abnormalities or deficiencies of immunoglobulins made by lymphocytes
- blood protein levels
- uric acid levels
- erythrocyte sedimentation rate (the speed that red cells settle at the bottom of a test tube - an increased rate can indicate cancer)
- liver and kidney function
- evidence of hepatitis A or B
- two biological markers, lactate dehydrogenase (LDH) and beta 2-microglobulin
Bone Marrow Tests
Your doctor may decide to examine your bone marrow to see whether the disease has spread. If your disease is in an early stage and some signs and symptoms haven't appeared, you may not need the test.
Bone marrow testing involves two steps usually done at the same time in a doctor's office or a hospital:
- a bone marrow aspiration to remove a liquid marrow sample
- a bone marrow biopsy to remove a small amount of bone filled with marrow
Your doctor may also take bone marrow samples during treatment to determine your therapy's effectiveness.
Other Tests for Specific Subtypes
Certain tests are performed for specific subtypes only and not necessary for all patients with NHL. They include:
- upper and lower endoscopies for patients whose disease involves the digestive (gastrointestinal) tract
- colonoscopy for patients who have mantle cell lymphoma
- a lumbar puncture (spinal tap) for patients whose central nervous system may be affected by NHL
- imaging of the brain or spinal column for patients whose central nervous system may be affected by NHL