MolDX and Z codes have been around for well over 15 years now, preceding by several years the new AMA CPT genetic coding system of 2012-2013.
How many Z codes are there? We can start to ballpark the number by going to the Dex Diagnostics Exchange Register, registering as a public user, and looking at the two catalogs. These are the TEST catalog and the "LABS & MFGRS" catalog.
Click on Lab Tests, and you'll have atable that is 179 pages at 100/page, and remarks, 17819 items.
Click on Labs & Mfgrs, and you'll see 33 pages at 100/page, and remarks, 3249 items.
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I don't know to what extend there are separate Commercial and Medicare listing, but this gives you a first approximation of the DEX Z-code library.
