The lower the free PSA, the more likelihood there is to be cancer (usually, less than 15 percent free PSA means you should have a biopsy). The reason? Cancer cells make compounds that enhance the binding of PSA, making the number an important clue if the PSA is in the borderline range of 4 to 10.
Another side note: PSA (which, to repeat, isn't cancer but indicates an irritation of the prostate) can be elevated by such things as urinary infection, bike riding, prostatitis, or having sex within 24 hours of the test.
Here's where PSA levels should be at various ages, remembering that an increase over time is more indicative of a problem than just a single test:
Age PSA Levels (nanograms of PSA per milliliter of blood, or ng/ml)
- 40–49 0 to 0.25
- 50–59 0 to 3.5
- 60–69 0 to 4.5
- 70–79 0 to 6.5
Find out more about this book:You: Staying Young: The Owner's Manual for Extending Your Warranty