I did a test for hormones in the past when the doctor saw a start of gynecomastia and wanted to test for prolactin (which, in men, could be a bad thing).
I was taking PM (circa 1000mg /day) and the test results said that my prolactine was fine, my E was within male level, and my T was quite high.
So, no, PM doesn't show in blood tests. And it's not even a T antagonist strong enough to lower your T drastically by itself.