You are right that prostatitis is very hard to diagnosis. There is seldom an infectious agent found in the urine, even after a prostate massage. And more often than not, antibiotics don't work. BPH is diagnosed by the size of your prostate. If your PSA divided by your prostate size is around 0.15 or less, BPH may explain it. Another way to diagnose BPH is to take Proscar or Avodart. After a few months, if your PSA drops (typically by about
half) and stays low, BPH is the culprit. On the other hand, if the medicine does not lower your PSA, or if it drops, but then rises while taking it, other causes are suspected.
There are several biochemical tests that can help you decide if a biopsy is worthwhile. The lowest cost, and perhaps better than the others, is called the "prostate health index" or PHI. It includes both PSA and free PSA. It is FDA-approved and covered by insurance (cost is $125 if it is not). Your doctor can order it for you through the following site:/www.accureference.com/phi/
PCA3 is expensive and is probably not covered by insurance before a first biopsy (because the FDA only approved it for after
a first biopsy). 4Kscore is also expensive (around $400) and not covered by insurance. There other tests: Apifiny, EPI, TMPRSS2:ERG fusion, etc. All are expensive and not FDA-approved, so insurance is unlikely to cover them.