Hi Tom, yes, I have posted along similar lines many times in the past to reassure other members. In actual fact, the tolerance range that you refer to is possibly slightly wider for PSA than in routine lab work; in my post regarding our last appointment with Mr P he stated that the range was 5/100ths so a single sample could produce a reading of anything from 0.01 - 0.05. This makes monitoring of men via ultra-sensitive PSA test more tricky than the simple 1 decimal point system because one result out of odds with previous ones can cause undue panic. However, the law of probability would suggest that while tolerance might lead to successive results which hover around 0.02, 0.04, 0.03 should not cause concern, a trend of 0.02, 0.03, 0.05 is too regimented to be ignored. Fortunately for us (and Ray who is a perfect example of fluctuating PSA) the ups usually seem to be followed by drops so I am not concerned.