What is your reason for changing labs? Are you concerned about
seeing fluctions in the ultrasensitive test, or do you need to change labs for insurance or geographical reasons? If you search my postings, you will see that I have asked this question on several occasions, however I have only had surgery. My personal reason for the consideration of a new lab and "conventional" PSA test is to reduce anxiety. I had a very good surgical outcome with a very low chance of recurrence and saw little benefit from seen ultrasensitive fluctions. However, I am not familiar with monitoring PSA after radiation. You will want the opinions of others on this.