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Additional Testing
The prostate-specific antigen (PSA) test is usually the first step in screening for prostate cancer, but a PSA result by itself cannot tell you whether cancer is present. Recent research has produced additional tests that, used alongside the PSA, digital rectal exam (DRE), and biopsy, give your doctor a clearer picture of two things: how likely a biopsy is to find cancer, and how aggressive that cancer is likely to be.
None of these tests is conclusive on its own. Think of them as ways to sharpen a decision, not replace it. Below we walk through the three most common additional tests, the Prostate Health Index (Phi), PCA3, and the 4Kscore, so you can understand what each one measures and talk them over with your doctor.
Why Additional Tests?
The PSA test is a valuable warning sign, but it is not perfect. PSA can be elevated for reasons that have nothing to do with cancer, such as an enlarged prostate or inflammation, which can lead to biopsies that turn out negative. Additional tests help answer a practical question many men face after a borderline PSA: is a biopsy really necessary right now?
By refining the estimate of risk, these tests can help you and your doctor avoid an unnecessary procedure or, just as importantly, move ahead with confidence when a biopsy is warranted. They are used in addition to the standard tests, not instead of them.
Phi (Prostate Health Index)
The Prostate Health Index, or Phi, combines three blood tests into a single, more accurate “Phi Score.” For a man with an elevated PSA, the Phi Score gives better information to determine the probability of finding cancer during a biopsy. Because it draws on more than the total PSA alone, it can help separate men who are likely to benefit from a biopsy from those who may be able to wait.
PCA3
PCA3 is a urine test that looks at the expression of PCA3, a gene specific to prostate cancer, to more accurately gauge the possibility of prostate cancer. The PCA3 score is most often used to help decide whether a repeat biopsy is needed after an earlier biopsy came back negative. Researchers have studied for years whether PCA3 could replace or serve as a substitute for the PSA test.
4Kscore
The 4Kscore is a blood test that provides a patient-specific probability of finding an aggressive form of prostate cancer during a biopsy. It measures four prostate-related proteins, total PSA, free PSA, intact PSA, and an enzyme called human kallikrein 2, then combines the results with your age and physical exam findings in an algorithm that estimates the percentage chance of aggressive disease. With that number in hand, you and your doctor can make an informed decision about whether to proceed to a biopsy.
Putting the Tests Together
While none of these tests is conclusive on its own, when performed alongside a PSA test, a digital rectal exam, and a biopsy, they give each man more information about his specific situation. That fuller picture can aid both the diagnosis and the decision about treatment. The right combination depends on your history and your PSA results, which is a conversation to have with your doctor.
Additional testing is one step in how prostate cancer is diagnosed. Still deciding whether it is time to start screening? Read our guide on when you should get tested or review your personal risk factors.
No Doctor or Insurance? We Can Help.
If you do not have a doctor, do not have insurance, and cannot afford screening, contact us to find out what free prostate screenings are available near you. Many take place in September, during Prostate Cancer Awareness Month.
Get a Free PSA Test in Nebraska
It all starts with a simple PSA blood test, and the Nebraska Prostate Cancer Alliance offers it free to men 40 and older at Cruisin’ for a Cure and community events across Nebraska. No insurance required. Results stay private. Early detection saves lives.
Keep Learning
Additional testing is one part of how prostate cancer is diagnosed. Explore the other steps and find out when you should start screening.