PSA Test vs. Free PSA Test

[Fox2018]

Hello All,

What is the difference between these two tests? I have always had an annual PSA Test for the last ten years. Now my urologist has ordered a follow-up Free PSA Test for early November.

Thanks for any feedback you can provide.

[Tall_Allen]

% free PSA is a bit more accurate than PSA alone. Still better is Prostate Health Index (PHI). PHI is covered by insurance and Medicare. Call your Uro and ask for it.

[Tall_Allen in reply to Tall_Allen]

I should have mentioned that PSA and % free PSA are part of PHI.

[Hidden]

PSA comes in several forms, mainly "bound", "free" and p2PSA". The bound form is where the enzyme is attached to protein molecules and the free form isn't. P2PSA is another more recently discovered form. The Prostate Health Index is a formula comparing the proportion of free PSA to the TOTAL amount and the amount of p2.

In simple terms, the greater the proportion of free PSA the less likely it is that raised total PSA is due to cancer.

The PHI is therefore a better indicator of cancer than just the total PSA test.

Some urologists now use it to decide if a biopsy is necessary.

I recently exchanged posts with a guy who's PSA was 8, DRE enlarged. He had the free test and didn't have a biopsy and was treated with alpha blockers.

If your total PSA over the years, it may be due to age, BPH or Prostatitis not necessarily cancer. The free test might suggest if a biopsy is needed or not, in your case.

Good luck.

[Hidden in reply to Hidden]

Damn, the PHI test isn't generally available in the UK, but now MRI is done before biopsy . For me, some years ago, it was the other way round. There's also some research into the usefulness of the PCA3 test which is a urine test.

The UK has mass screening programs for some cancers, I.e. breast, cervical and colorectal, but NOT prostate. This is because it's argued that the PSA test is so unreliable and in itself gives no indication of how aggressive it is.

Perhaps the fact that this last year more men died from PCA than breast cancer might mean current practice is reconsidered especially if the urine test is shown to be useful.

[FCoffey]

Ordering a free + total PSA test is usually done to help determine if cancer is present.

PSA can be elevated by inflammation, infection, even recent ejaculation. The ratio of total and free PSA tends to be different in cancer than with other causes.

"Tends to be." There is no PSA test that can confirm or deny the presence of cancer. What's worse, even when cancer is confirmed with MRI or biopsy, there is presently no way to know if it will be a slow-growing cancer that poses no real risk to the patient, or a dangerous one that is likely to cause an early death. This inability to distinguish the large fraction of cancers that are not a threat leads to over treatment and all the terrible side effects that come with it.

Neither test is more accurate; adding the measurement of free PSA to total PSA gives additional information, that's all. Both tests are as accurate as the present technology and instruments allow.

Good luck!