Hi DryGuy,
I had a prostatectomy 21 months ago. After surgery, my first couple of PSA tests were done at the hospital. They measured to a lower level (<0.025 in my case). The surgeon described this as "undetectable" PSA.
I was then switched to having the tests done by my G.P. Presumably, they use a different lab, and my results have been <0.1. But the same surgeon describes these results as "undetectable" also.
So, I would suggest that you probably have nothing to worry about.
Best wishes,
JedSee.