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Haematology

What is flow cytometry?

global diagnostics tool
global diagnostics tool

Katherina Psarra

President, European Society for Clinical Cell Analysis

Flow cytometry plays an integral role in helping doctors to detect diseases like blood cancer, and determine the best treatment pathways. But how does it work?


Flow cytometry is a vital technology used in the diagnosis and monitoring of a range of health disorders, particularly haematological cancers, immune deficiencies and HIV infection.

The technology works by detecting the type of cells present in body fluids, such as blood, bone marrow and cerebrospinal fluid, or wherever a single-cell suspension can be made from cell culture or tissue samples.

On entering the flow cytometer machine, the cells in the sample marked with detectable fluorescent dyes coupled to antibodies that are directed against appropriate cell structures has a laser beam directed at it. A series of electronic detectors then measure the degree of fluorescence emitted by the cells to determine its various properties. The process enables medical staff to recognise specific diseases and to distinguish between the different types of haematological malignancies that exist, such as leukemia and lymphoma, enabling treatment to be tailored to the type and stage of a patient’s disease.

A global diagnostic tool

Flow cytometry is an essential diagnostic tool for haematologists and immunologists all over the world. Not only does the technology enable precise diagnoses, it also allows residual levels of disease to be detected following a course of treatment.

Before flow cytometry was developed, physical samples had to be analysed under a microscope—a process that only allows a counting of a few hundred cells and determining one or two structures on a cell at any one time. For a haematologist looking for evidence of any residual cancer cells in a patient’s body after treatment, it was not possible to measure residual aberrant cells.

Faster computers, smarter software, more powerful lasers and better electronic detector apparatus mean it’s now possible to count millions of cells, thanks to flow cytometry. What’s more, it enables the data from a sample to be analysed very quickly, so patients can find out in a very short space of time whether their treatment has been successful or not.

As well as cell diagnostics, flow cytometry also plays an integral role in genetics, immunology and biomedical research.

While flow cytometry training is not a standard undergraduate requirement in medical or biology degrees, certified postgraduate courses are available to take for those who already possess medical or biological sciences experience. The European Society for Clinical Cell Analysis (ESCCA) offers such education at ESCCA courses and conferences as well as the opportunity of becoming a certified cytometrist through ESCCA exams.

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