I've been having my PSA checked every year for over ten years and I keep a chart on it so I can watch the progression from year to year and it is consistently in a range from 1.7 to 2.3. Then I went on Proscar and my first PSA while on the drug was way low. I had done my homework and was expecting it but my question is this - there has to be some factor to apply to that low reading in order to compare it to what it was prior to going on the drug. In other words, let's say it was a 2.0 last year, then I start taking the drug and now it drops down to .5 or some rediculously low number. I would use some factor to multiply times the .5 to give me a realistic number for comparison purposes. Thought maybe someone out there has been down this road already and would have a clue.