cytometria

Cytometría (cytometry) is a set of techniques for measuring physical and chemical characteristics of cells or particles. It commonly relies on optical and electronic detectors to analyze large numbers of cells quickly, yielding quantitative data on size, internal complexity, and specific biomarkers labeled with fluorescent tags. The field encompasses several modalities, including flow cytometry, imaging cytometry, and mass cytometry (CyTOF), as well as cell sorting by fluorescence (FACS).

Flow cytometry passes cells in a fluid stream through one or more laser beams; detectors record forward scatter (size), side scatter (granularity), and fluorescence from labeled antibodies. Multiparameter instruments can measure dozens of parameters per cell. Fluorescence-activated cell sorting (FACS) allows physical separation of cells that meet predefined criteria. Imaging cytometry combines microscopy with automated analysis to assess morphology, spatial distribution of markers, and multiple channels in adherent or suspended cells. Mass cytometry couples antibodies to rare earth metal isotopes and detects signals with time-of-flight mass spectrometry, enabling high-parameter phenotyping without spectral overlap.

Applications include clinical immunophenotyping of blood cells for leukemia and lymphoma diagnosis, monitoring of immunotherapies, transplantation, and minimal residual disease; in research, cytometry is used for cell signaling, cell cycle analysis, apoptosis assays, and cytometric bead-based assays. Data analysis commonly uses gating strategies to identify cell populations, compensation to correct spectral crosstalk, and calibration with reference beads. Standardization efforts aim to improve reproducibility across laboratories.

Equipment ranges from benchtop flow cytometers to high-content image cytometers and specialized mass cytometers. Proper sample preparation, staining protocols, and instrument calibration are essential for reliable results.