Quantitative Flow Cytometry Measurements in Antibodies Bound per Cell Based on a CD4 Reference

Area of Science:

• Clinical laboratory diagnostics
• Immunophenotyping
• Biomarker quantification

Background:

• Multicolor flow cytometry is vital for measuring cell numbers and receptor expression, serving as disease biomarkers.
• Current methods lack standardization, hindering clinical utility and instrument independence.

Purpose of the Study:

• To detail a procedure for quantifying surface and intracellular biomarkers using flow cytometry.
• To establish a standardized method for biomarker measurement in antibody-bound-per-cell (ABC) units.

Main Methods:

• Flow cytometer quality control.
• Fluorescence intensity calibration with microspheres.
• Compensation for fluorescence spillover.
• Application of a biological reference calibrator for ABC scale establishment.

Main Results:

• A detailed protocol for calibrating multicolor flow cytometer output.
• Quantification of biomarkers in antibody-bound-per-cell (ABC) units.
• Foundation for instrument-independent biomarker measurements.

Conclusions:

• The described procedure enables standardized, quantitative biomarker measurement via flow cytometry.
• This approach enhances clinical relevance and facilitates inter-laboratory comparisons.
• Ongoing efforts aim for universal instrument and reagent independence in biomarker quantification.