Flow cytometry

This page was reviewed under our medical and editorial policy by

Bradford Tan, MD, Chair, Department of Pathology and Laboratory Medicine, City of Hope Atlanta, Chicago and Phoenix

This page was updated on June 7, 2023.

Flow cytometry is a diagnostic tool that may help doctors diagnose, stage and follow the treatment progress of a cancer patient. With flow cytometry, laser technology is used to measure properties in cell samples taken from a patient. The lasers measure individual cells in the body, after they’ve been treated with a fluorescently stained antibody. As the laser passes over the cells, the cells emit a certain type of light that’s then converted into an electronic signal for computer analysis. The results of the analysis help doctors identify the properties of a cell.

The technology behind flow cytometry is recent and has made it easier for medical professionals to understand both the immune system and the biology of cells, which is why it’s useful for cancer patients.

This overview will cover the basic facts about flow cytometry, including:

What is a flow cytometry test?

A flow cytometry test can be used on cells found in various parts of the body, including cells from:

  • Tissue samples
  • Blood
  • Bone marrow

During the procedure, cell samples are stained with a dye that makes them more sensitive to light. Next, they’re placed in a fluid, and beams of light are shone through, with the light reacting to the dyed cells. Based on the reactions from the light, doctors are able to look for the presence or absence of antigens in the cells, which helps them diagnose and monitor certain types of cancers.

What is a flow cytometry test used for?

Flow cytometry has a wide range of uses, but it’s most frequently used for immunology, or the study of the immune system. Through a procedure called immunophenotyping, doctors measure the amount of protein in specific types of cells. This procedure is frequently used in T-cells, a type of white blood cell that assists the immune system. Because of its use with T-cells, flow cytometry is used as a diagnostic tool for many types of leukemia and lymphoma.

Some types of cancer that may be diagnosed with immunophenotyping include:

If a patient is suspected of having a type of cancer that may be diagnosed with flow cytometry, his or her care team will explain which types of cells are being tested and what to expect from the procedure.

Flow cytometry may also be used for a wide range of other purposes, including:

  • Counting and sorting cells
  • Determining the cancer’s biology, which helps doctors better understand the development and growth of cancer cells 

How to read flow cytometry results

After a flow cytometry test, the doctor will analyze the results. Because cell counts for different types of cells vary with age, the test results will be compared to normal results for a healthy person in that age group. Software programs are used to analyze the light scatter patterns produced by the test. Based on the results, doctors may:

  • Diagnose a patient with cancer
  • Determine the stage of the cancer
  • Recommend appropriate treatment options

Patients should speak with their doctor to learn more about their specific flow cytometry test results

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