WADA made a concerted push on the evidence from a mass spectrometer reading of what it argues was thymosin beta-4 – the banned substance the players are accused of being administered – by calling a second expert from Canada, in addition to ASADA's expert witness David Handelsman, to give evidence on the "second batch" of alleged TB4. The mass spectrometer reads the molecular weight of a substance and while this was close to a match for TB4 (4971 compared with TB4's 4963, as measured by Bio21 at Melbourne University), it was only one of two batches of the substance ASADA and WADA claimed were compounded and given to Stephen Dank by chemist Nima Alavi. The CAS has to be "comfortably satisfied" TB4 was administered to specific players.
I'm no scientist but 4971 to 4963 is a difference of only 8.
that's less than .1 of a % away from TB4.
Of course the machine would have some error factor built in, but I'm willing to guess it's probably in the range of half a %