Flow Cytometry

Flow cytometry is a laser-based technique used to detect and analyze the chemical and physical characteristics of cells or particles. It is most commonly used to evaluate bone marrow, peripheral blood and other fluids in your body.


What is flow cytometry?

Flow cytometry is a lab test used to analyze characteristics of cells or particles. During the process, a sample of cells or particles is suspended in fluid and injected into a flow cytometer machine. Approximately 10,000 cells can be analyzed and processed by a computer in less than one minute.


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What is flow cytometry used for?

Specifically, flow cytometry is used in research for a number of purposes, including:

  • Cell counting.
  • Cell sorting.
  • Determining cell function.
  • Determining cell characteristics.
  • Detecting microorganisms, such as bacteria, fungus or yeast.
  • Finding biomarkers (characteristics that indicate normal function).
  • Diagnosis and potential treatment of blood and bone marrow cancers.

When is a flow cytometry test necessary?

Flow cytometry may be used to characterize and count types of white blood cells in the evaluation of infectious diseases, autoimmune disorders or immunodeficiencies. It’s also used to diagnose and classify leukemia or lymphoma. Flow cytometry is generally used as follow up testing after a complete blood count (CBC) or white blood cells scan (WBC). This is especially true if initial testing showed an increased number of lymphocytes, abnormal cell counts or the presence of immature blood cells. Healthcare providers use flow cytometry to predict how aggressive the cancer will be and to help determine if the cancer will respond to certain treatment. It can also tell you if disease has relapsed (returned) after treatment.

Flow cytometry may be used whenever your healthcare provider needs to learn more about the cells inside your body. This type of testing can check the number of immune cells, assess your cell cycle status, identify cancer cells or even analyze your DNA. Researchers use flow cytometry any time they want to learn more about the complexities of certain conditions and diseases.


Who performs flow cytometry?

Lab technicians or pathologists perform flow cytometry. The test requires a sample of blood, bone marrow, tissue or other body fluid. The sample is taken by your healthcare provider.

Test Details

How does flow cytometry work?

Your sample of blood, bone marrow or tissue cells is placed in a suspension and injected into the flow cytometer machine. The cells are arranged in a single file line, and then passed in front of a laser beam, scattered light and fluorescent light. Next, the cells are counted and categorized. The data is stored in a computer and reported via a histogram or dot plot.

Multicolor flow cytometry

If different types of cells are being tested at the same time, such as blood and tissue cells, multicolor flow cytometry is a useful approach. Specific cell types are marked with fluorescent dye. The flow cytometer machine then sorts the cells by type and color.

Flow cytometry gating

“Gating” is a basic principle of flow cytometry. It refers to the process of identification and refinement of a specific cellular population. To do this, the pathologist can select an area on the computer-generated chart. This will tell the flow cytometry machine which cells to keep analyzing and which ones to stop analyzing.


What should I expect before a flow cytometry test?

Unless your healthcare provider gives you specific instructions, there is usually no need for preparation before having a flow cytometry analysis. You will simply visit your provider’s office where they will obtain a blood, bone marrow or tissue sample.

What should I expect after a flow cytometry test?

Once the flow cytometry test is completed, your healthcare provider will analyze the results. They’ll schedule an appointment to discuss their findings with you.

What are the risks of flow cytometry?

There are no known risks to having a flow cytometry test.

Results and Follow-Up

How are flow cytometry results interpreted?

A pathologist (a healthcare provider who specializes in lab testing) will interpret your flow cytometry results and place their findings in a comprehensive lab report. Your pathologist will consider the results of your flow cytometry analysis as well as your medical history, symptoms and most recent physical examination.

Specifically, your provider will look at the markers (antigens) on your cells. A healthy cell will show a pattern of antigens that match the type and maturity of the cell. An abnormal cell will show different patterns that may suggest the presence of leukemia, lymphoma or other diseases. Abnormal results are usually found in the presence of:

What happens once my test results are in?

Your healthcare provider will discuss your flow cytometry results in detail and talk about possible treatment options. A flow cytometry test can tell your medical team how aggressive your condition is, how likely it is that a certain treatment will work and how likely your condition is to relapse after treatment is complete. When talking about your potential treatment, all of these factors will be taken into account.

A note from Cleveland Clinic

Flow cytometry may be recommended if your healthcare provider needs to detect, identify or count specific cells. It may be used to assess cells from your blood, bone marrow, tumors or other body fluids. Thanks to this advanced technology, healthcare providers can recommend more accurate care based on your specific needs.

Medically Reviewed

Last reviewed on 11/17/2021.

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