Coulter Flow Cytometry

A Coulter counter detects changes in electrical resistance as cells pass through a small opening, helping count and size them. Flow cytometry passes cells through a laser and analyses their light-scattering and marker patterns. Some laboratory instruments combine these approaches, which is why the terms may appear together.

Cell size and internal complexity create part of the pattern. Fluorescently labelled antibodies can identify proteins on or within cells, allowing the laboratory to separate cell populations that look similar under a microscope.

In oncology and haematology, this immunophenotype can support the classification of leukaemia, lymphoma and other blood or marrow disorders. A report may list marker names, cell populations and an interpretation. No single marker should be read in isolation; the pattern is considered with blood counts, cell appearance, symptoms and other test findings.

Preparation depends on how the sample is collected. A routine blood draw generally needs no special preparation unless the care team gives instructions. A marrow sample involves a separate procedure with its own preparation and aftercare.

Tell the team about medicines, bleeding problems and any previous reaction to antiseptics, dressings or local anaesthetic. The sample must contain enough intact cells, so the laboratory may request another specimen if cells have broken down, clotted or are too sparse for a reliable interpretation.

Flow analysis itself happens in the laboratory and does not cause symptoms. After a blood draw, seek advice if the puncture site has persistent bleeding, increasing redness, swelling or pain. Following marrow sampling, use the specific wound-care and activity instructions provided by the clinical team.

Get urgent help for uncontrolled bleeding, rapidly expanding swelling, fainting, breathing difficulty or signs of a severe allergic reaction. Contact the ordering clinician if symptoms are worsening while results are pending; laboratory turnaround should not delay assessment of an unwell person.

Useful questions include which sample was tested, what cell population the report describes, whether the pattern is abnormal, and which other results are needed before a diagnosis can be made. Also ask whether the sample quality limited interpretation and when the full set of findings will be discussed.