When you send it in, you also indicate what kind of oil it is (eg, Redline 5W40, or ATF T-IV....etc.), miles and vehicle. The lab knows what the baselines and minimums are for that lubricant. Then, test it against those baselines, plus for any contaminants. So, when you send in a sample of an oil that is Redline D4 ATF, they know what the universal averages are and what to look for in terms of trouble. There are certain maximums (contaminants, oxidation, acidity, etc) and minimums (viscosity, baseline, etc) that are allowable. An oil within spec is a good oil....period. It's performing the function for which it was designed.
Next, actually, ATFs are pretty much all the same....for the most part anyway. Saying this can cause one of those ridiculous "oil debate" things......but.......it's just true. I was going to go into this....but figure that's for another thread. Let me just say that I use Redline D4 in my transmission.