What is the lowest a regular PSA Test can read?

Morning gentlemen;

I recently got my 29 month post brachytherapy PSA result in last week, and the result was .20 . That's the same reading as I got from my test 4 months ago in February, and from the same lab. I guess I was hoping the reading would continue to drop, and be in the neighborhood of .10. I was wondering how low the regular PSA test can read, and if I should start requesting the ultra sensitive test ?

The "regular" test is good for one decimal place or to answer your question the lowest it can read is 0.10.
It appears that your numbers so far are carried to two decimal places indicating that you are getting a more sensitive test than the "regular". So it appears that your testing as now being done will read down to 0.01. I don't know if it is called ultra sensitive or not as there are some labs the provide results to three decimal places, which in that case your could get results as low as 0.001.
I think you will be fine with your present testing as it appears to be able to provide results down to 0.01. It looks like you are heading in that direction!

I notice that from 11/12 to 2/13 your PSA actually went up a whopping 30%, and then started going back down over about a year to levels about 80% lower than that jump up to 1.6.

So I wouldn't worry too much about not yet going below 0.2, you will probably get there. Even if it doesn't, back in 1997 Dr. Critz out of Atlanta (Prostrcision (sp?) ) has stated:
http://www.ncbi.nlm.nih.gov/pubmed/9123692
"RESULTS:

Eighty-one percent of all men are calculated to achieve a prostate-specific antigen nadir of 0.5 ng/mL or less and to have a 5- and 10-year disease-free survival rate of 93% and 83%, respectively, as compared with a 5-year disease-free survival rate of 26% for those achieving a nadir of 0.6 to 1.0 ng/mL--a significant difference (P = 0.0001). All men with a nadir greater than 1.0 ng/mL ultimately failed treatment. Of 201 men with a minimum 5-year follow-up, 143 are disease-free and 140 (98%) achieved and maintained a nadir of 0.5 ng/mL or less.
CONCLUSIONS:

For possible cure of prostate cancer with radiotherapy, a prostate-specific antigen nadir of 0.5 ng/mL or less should be achieved. With this nadir level, disease freedom after irradiation is defined as achievement and maintenance of a nadir of 0.5 ng/mL or less. A nadir greater than 0.5 ng/mL or subsequent increase above 0.5 ng/mL is defined as irradiation treatment failure. This definition may help resolve the controversy about the potential for cure of prostate cancer by irradiation."

But later he has said: http://www.ncbi.nlm.nih.gov/pubmed/10604691
"CONCLUSIONS:Primarily on the basis of the results from men treated with simultaneous radiation using the transperineal technique, the definition of disease freedom for radiotherapy should be men who achieve and maintain a PSA nadir of 0.2 ng/mL or less."

Either way, you have reached both of those goals and exceeded one of them, though admittedly those studies were not done on advanced cases(T1s and T2s median starting PSA 8 Gleason?) and I'm not certain non-recurrence would have been as high if he started with G9s and T3s+. Still, even if survival was lower with more aggressive cases, they may well have never reached a nadir of even .5, much less .2.

So unless your PSA starts rising and continues rising, I'd say the odds are with you!
Bill

John T.,

Do you think I've already had my nadir of .2 , or I still might have a ways to go ? I've read some of the above studies that quote .2 as the cutoff for success vs failure of radiation therapy, and I was hoping for a little more wiggle room with a lower number.

powelist,
I don't think anyone can tell you what your nadir will be or when you will reach it. It just differs so much between patients. I can only tell you that those are excellent results and you should be celebrating and not worrying.

My uro and RO cooperated, but they certainly had different objectives. The RO was there to administer RT, did that, and after my first post RT PSA told me that I now passed back to the uro, and that there would be no further interaction needed between us. She then left practice to go raise a family.

I think that a similar disconnect is very common. Don't blame your uro for it. ROs do RT. Uros do urology, and maybe surgery.

That's why I have a uro and an oncologist.

A "standard" PSA test will report down to "<0.10". You have to ask for ultra-sensitive to get below that. From what I learned while researching Rt as a primary treatment, you should be screaming for joy in the streets.