Flow Cytometry: A Basic Introduction

A sample such as blood, bone marrow, or another cell-containing fluid is prepared so cells pass through a narrow stream. Lasers illuminate each cell, while detectors record scattered light and signals from attached markers. The pattern can show cell size, internal complexity, and surface or internal features. In oncology, these findings may help classify blood-related disorders and add detail to other investigations. Flow cytometry is a method of examining cells; it is not, by itself, a complete diagnosis.

Tell the care team about medicines, recent infections, or transfusions if asked, because context helps the laboratory interpret the result. Follow instructions for the specific sample. Results are considered alongside symptoms, examination findings, imaging, and other laboratory or tissue tests. Read the report with the clinician who ordered it. The [Flow Cytometry](/technology/flow-cytometry/) page gives broader context.

Contact the clinical team for heavy bleeding, increasing redness or swelling, worsening pain, fever, fainting, or shortness of breath after a sample-collection procedure. A bone marrow sample can leave local soreness. Seek urgent help for severe breathing difficulty, chest pressure, confusion, or collapse.

Ask which sample will be tested, what the laboratory is looking for, and whether the result is intended to classify cells, monitor a known condition, or guide another test. Clarify when results may be available and whether a further procedure such as a [Bone Marrow Biopsy](/treatments/diagnostics-and-staging/bone-marrow-biopsy/) is being considered.