Discover all of the different techniques and tools that might be used to assess response to treatment in blood cancers.
Complete Blood Count (CBC) is a test that measures the number of different types of blood cells
(e.g., red blood cells, white blood cells and platelets) in a sample of blood. Your doctor may want more specific information about the various types of white blood cells, in which case they will order a CBC “with differential”. You may have had a CBC test during an annual physical, as it is often used to check an individual’s overall health.
Microscopic examination is a technique your doctor will use to supplement the information gained from the CBC test. A bone marrow sample (either an aspirate sample or a biopsy) or a blood sample can be used, depending on the clinical context. The sample will be put onto a glass slide, treated with different stains, and looked at with high magnification. Your doctor will be looking to see whether the right numbers/ratios of different cell types are present, whether any of the cells look abnormal, and whether the cells are maturing correctly.
Immunohistochemistry (IHC) uses antibodies tagged with a dye to look for a specific marker. The antibodies will stick to cells in a blood, bone marrow or tissue sample that have the marker of interest and be visible under a microscope. Immunohistochemistry is used to help differentiate cancerous cells from healthy cells.
Fluorescence in situ hybridization (FISH) is a test that looks for specific abnormalities in the chromosomes of cancer cells. These abnormalities can include translocations, inversions, deletions or duplications and can sometimes impact prognosis. A probe with fluorescent dye is added to the cancer cells that will stick to abnormal chromosomes and be visible under a microscope.
Cytogenetic testing examines the chromosomes in the cancer cells, looking at their number, size, arrangement and shape. In some blood cancers (e.g., CML), it is used to find a specific chromosome known as the Philadelphia chromosome, and cytogenetic testing can be used to assess treatment response by looking for the number of cells containing the Philadelphia chromosome before, during and after treatment.
The Free Light Chain (FLC) assay is a more sensitive technique for detecting specific pieces of the M protein called kappa and lambda light chains in the serum. This method can be useful when a person does not release high amounts of M protein (i.e., amounts not measurable using immunofixation or electrophoresis). Serum FLC testing can be used to diagnosis myeloma. Your doctor may also use it for assessing response to treatment or for monitoring.
Immunofixation (also called Immunofixation Electrophoresis or IFE) is used to find the myeloma protein (also commonly called M protein, M component or M spike) produced by myeloma cells in samples of serum or urine. Immunofixation can more sensitively detect M protein than electrophoresis and is also used to determine the type of M protein a patient’s myeloma cells produce.
Electrophoresis (also called Protein Electrophoresis or PEP) is used to measure the amount of myeloma protein (also commonly called M protein, M component or M spike because of how it looks on the graph) produced by myeloma cells in samples or serum or urine (based on sample used the test might be called SPEP or UPEP). High levels of M protein are generally an indicator of advanced myeloma and can negatively affect certain parts of the body, including the immune system and kidneys.