Microtomy Tracking Sheet for CODEX Specimens The process of sectioning CODEX specimens presents tediously at the tissue block trimming and microtomy stage. As you begin to cut into a new or already used tissue block, you must keep track of how many microns of tissue are removed from the section during trimming, and also during microtomy. Attached is a generic document that is used to keep record of what tissue block is being cut. All identification factors, trimming data, what tissue sections were used and their purpose, as well as storage information. Formal logging of how far into the tissue block you have traveled as well as how many sections were used is an extremely important and necessary function in this process.