The goals with testing are to diagnose and stage lymphoma, to distinguish it from other conditions, and to identify and monitor any associated complications. There are few blood tests that clearly indicate lymphoma.
The gold standard diagnostic test for both Hodgkin lymphoma and non-Hodgkin lymphoma is the examination of involved lymph nodes or lymphoid tissue by a pathologist. The sample is usually collected from an affected lymph node or tissue using a biopsy or fine needle aspiration procedure and is examined under the microscope. (To learn more about biopsies, read the article on Anatomic Pathology.)
Other laboratory tests that may be useful include:
- Complete blood count (CBC) – may be ordered to rule out non-lymphoma conditions (such as leukemia) and/or to see if anemia is present. A CBC can determine if the platelet count and/or white blood cell count are low, which may indicate that lymphoma is present in the bone marrow and/or blood.
- Bone marrow biopsy and examination – used to evaluate the cells present in the bone marrow. The presence of abnormal lymphoid cells and/or lymphoid aggregates may be seen with lymphoma.
- Blood smear – used to evaluate the quality of red and white blood cells and platelets as well as abnormal cells (lymphoma cells, for example), if present.
- Immunophenotyping can identify the cells involved by testing for the presence or absence of certain markers on the membrane of the cells or inside the cells. These commonly used markers are called clusters of differentiation (CD) and are listed numerically. By developing a list of the CDs present on the cells, it is possible to classify the cells. This test can be done by several different methods, including flow cytometry and immunohistochemistry.
- Chromosome analysis – an evaluation of the chromosomes in the nucleus of cancer cells to determine if pieces of the chromosomes have moved (translocation). This is rarely used for lymphomas.
- Molecular genetic analysis – evaluating the cancer cell's DNA for genetic changes, particularly to determine whether all of the cells belong to a single clone. (See B-cell Immunoglobulin Gene Rearrangement and T-cell Receptor Gene Rearrangement.)
- If it is thought that lymphoma has spread (metastasized) to other areas of the body, analysis of cerebrospinal fluid or other body fluids may be performed.
- Beta-2 microglobulin – this test may be used to help predict the prognosis.
- Serum creatinine – levels may be elevated if a kidney disease called nephrotic syndrome is associated with Hodgkin lymphoma
- Serum chemistry studies, including lactate dehydrogenase (LDH) – to help determine the prognosis
- Hepatitis B – this testing is done for patients who will undergo rituximab therapy because there are negative side effects associated with that treatment and hepatitis B
- Human immunodeficiency virus (HIV) testing – this is recommended because treating people with antiretroviral can improve their lymphoma outcome if they have HIV
Primarily used to help stage and monitor lymphoma, non-laboratory tests include:
- Physical examination
- Computed tomography (CT) scans
- Positron emission tomography (PET) scan
- Chest X-ray
- Exploratory surgery (occasionally necessary)
- Magnetic resonance imaging (MRI)
For more on these imaging studies, visit RadiologyInfo.org.