Absolute quantitation vs. semi-quantitative analysis of biomarkers expression using image analysis software

STP 2024 -- Expression of proteins/mRNAs can be quantitated semi-quantitatively using a microscope or digitized images for biomarker studies. The output of semi-quantitatively analyzed images are presented as minimal, slight, moderate, marked, or severe, which can be converted to a representative "percent range" as minimal (1-20%), slight (11-25%), moderate (26-50%), marked (51-75%) or severe (76-100%). However, using image analysis software, the percent change for a particular marker can be presented precisely. The main goal of this study was to compare semi-quantitative manual analysis with absolute quantitation generated via digital image analysis algorithms for area quantification, cell-based measurements (membrane, cytoplasm or nuclear), object-based quantification for protein expression or probe quantification for mRNA.