Technical Note: Measuring the thickness of histological sections by detecting fluorescence intensity of embedding foam.

Fluorescence intensity of embedding foam in paraffin blocks can be used to measure the thickness of histological microsections. We embedded samples of embedding foam and produced several microsections of varying thicknesses using routine processing and staining. Fluorescence intensity in the blue area of the embedding foam detected with a slide scanner was compared to absolute thickness as measured using confocal microscopy. Correlation analysis displayed a clear linear correlation with convincingly low prediction interval. The concept of measuring thickness of histological microsections by detecting fluorescence intensity of embedding foam is suggested as an approach to high-throughput measuring of histological sections applicable for a fully digitized pathology department. No acquisition of dedicated equipment is required and the method can be applied as a fully automated technique requiring no time consumption.