First post-surgery blood will be drawn this week (31 days after surgery) and see the Dr next week for results. From what I read here on HW, that may be a bit soon but trust the Dr knows why he's asking for it at this point.
You'll be fine, with your (relatively) low pre-surgery PSA test timing.
The PSA half-life is an easy calculation. For the vast majority of majority of men undergoing surgery who also relatively low pre-surgery PSA like you, 4 weeks is plenty of time for PSA to be flushed out of your system, and I'll demonstrate below. Four weeks does start to cut thing a little close, especially if your surgeon prescribes the ultra-sensitive PSA test for you, which is why more commonly the first test is done 6-weeks post surgery just to add a little more "margin." (BTW, the ultra-sensitive test is going to be appropriate in your situation simply because of your unusual, confounding numeric outcome results.)
The factor you need to know is that with a high degree of consistency, men's PSA diminishes by half, in the absence of other contributions, every 2-3 days. Just to be conservative, let's use 3 days for the calculations. If you were to use 2 days in the calculation, it would diminish faster.
So here's the easy math. Your pre-surgery PSA bounced around, which indicates that the total PSA was likely the combination of both your PC PLUS some non-cancerous cause(s). That's ok, for ease of calculations, let's round UP (also being conservative) to a starting point on the day of surgery to 8 ng/mL (which is also makes the math really easy):
Day 0 = 8 ng/mL
Day 3 = 4 ng/mL; the amount reduces by half in 3 days
Day 6 = 2
Day 9 = 1
Day 12 = 0.50 ng/mL
Day 15 = 0.25
Day 18 = 0.125
Day 21 = 0.063
Day 24 = 0.031
Day 27 = 0.016
Day 30 = 0.008 ng/mL
So, you can see that even using TWO conservative assumptions you should be fine after 30 days. Good luck.
Post Edited (JackH) : 6/15/2015 11:45:05 AM (GMT-6)