The latter. My health team says that for patients in my situation that they use the standard test that doesn't go into the additional decimal points. So, when I get my results, it will say "19.0" or "0.4" or "< 0.1". I have been "< 0.1" for the past 6 tests over the last 10 months.

My Johns Hopkins MO just uses < 0.1 as undetectable. I get my labs drawn out of state (at Labcorp) and they don't use the ultra sensitive test. My Radiation Therapy was performed at Emory. Following my 37 pelvic radiation treatments they tested my PSA and they do use the ultra sensitive test and the result was undetectable, i.e. < 0.014. My JH MO believes there is too much fluctuation in the ultra sensitive test and he won't consider Imaging until my PSA is >0.1.