Hi,
There is so much variability in the world of PSA numbers. Then we try to analyze a lab result to the nearest hundredth. Results can vary from lab to lab, the time of day of the test, what you did yesterday or even the day before. Results from your normal labs do a regular test, not a sensitive one. Therefore their PSA test only reports down to 0. If your level is below that, then it’s reported as undetectable.
Sincere my surgery in Jan. 2022, I’ve been tested every three months with a variety of reports. At 74, I’ve decided to cling loosely to my death, for there-in you find life. Best wishes with you PSA management and health.