We composed an early version that focused on the basics. It was based on content provided by Intermountain Healthcare, from a joint National Library of Medicine and Regenstrief Institute project analyzing raw units from more than 23 laboratory sources, and from the HL7 table of units. We excluded the units of measure for which we couldn’t find clear definitions or patterns of usage, those we believed would only be used in pharmacy dispensing, and units used for purely clinical reporting (e.g. cigarette pack-years). We have included most of the pure metric units from our sources, whether or not they apply directly to lab testing because they will be generally useful—and are pretty straightforward in UCUM.
The process used to generate this table is described in the Preface. We have made several iterative improvements in new versions.