Quantitative phase imaging comparison of digital holographic microscopy and transport of intensity equation phase through simultaneous measurements of live cells

•Digital holographic microscopy (DHM) and transport of intensity equation (TIE) phases are compared using simultaneously captured data.•TIE/DHM retrieved thickness reconstructions of a microlens target, and optical thickness measurements of C6 glial cells, are shown.•TIE/DHM retrieved relative optical volume curves are shown for C6 cells undergoing cell death.•Agreement between the techniques is shown, possibly encouraging adoption of TIE in labs without optical engineering experience.