Is PHI an Accurate Test for Prostate Cancer?

June 9, 2025

Jason Ferrier

What is the PHI test for prostate cancer?

After skin cancer, prostate cancer is the most common form of cancer for men in the United States. Approximately 1 in 8 men will be diagnosed with prostate cancer in their lifetime. For years, the Prostate Specific Antigen (PSA) test has been used as a screening tool for prostate cancer. PSA is a protein produced by the prostate gland. Elevated levels of PSA can indicate the presence of prostate cancer. However, there are limitations to the accuracy and specificity of a PSA test. Not all cases of prostate cancer will cause elevated PSA levels. There are also conditions other than prostate cancer that can cause a rise in PSA levels. Because of this, PSA testing is not considered an accurate tool for diagnosing prostate cancer. Additional tests, including a digital rectal exam or biopsy, are usually needed to diagnose or rule out cancer. Recently, a new test called the Prostate Health Index (PHI) has been gaining popularity as an alternative to the PSA test.

How to understand PHI test results

PHI is a blood test that measures three forms of PSA: total PSA, free PSA, and p2PSA. From these measurements, a person's PHI is calculated. This can help determine the likelihood of prostate cancer with more reliability than a PSA test alone. This, in turn, can reduce the instances of unnecessary biopsies or other more invasive forms of screening. The National Comprehensive Cancer Network had recommended the PHI test for men who had inconclusive results from a PSA test.

The 3 components of the PHI test are:

Total PSA: This measures the overall amount of PSA in the blood.
Free PSA: This measures the amount of PSA that is not bound to other proteins in the blood.

p2PSA: This is a specific form of proPSA, a precursor to PSA.

A PHI test begins by measuring PSA levels. If these are within normal levels, no further testing is necessary. If the PSA is between 4.0 and 10.0, additional testing will be performed for Free PSA and p2PSA. Using these measurements, a person's PHI score is calculated with the formula (p2PSA / free PSA) * √PSA. Generally, the higher a person's PHI score, the greater their risk of prostate cancer.

Is the PHI test more accurate than PSA?

While the PHI is not a perfect screening tool, it is considered more accurate than a traditional PSA blood test. Not only is the PHI test more accurately able to detect prostate cancer, but it can also help to evaluate a person's risk of developing prostate cancer and how severe their case may be. This can help a person's doctor develop the most effective methodology for future screenings and treatment if necessary. It is important to remember that even the PHI test cannot diagnose or rule out prostate cancer by itself. Certainly, a high PHI score should be discussed with your doctor. However, even someone with a lower PHI score should still consult their doctor to discuss their risk level from age and other factors.

Where can I get a PHI test?

Request A Test offers direct-to-consumer lab testing that anyone can order. This means that you can order a PHI test without having to first visit your doctor or get approval from your insurance provider. Just place an order online or over the phone and go to one of over 7,000 testing locations we partner with. Prostate cancer is a major health concern for men in the USA. If you are at risk, you deserve the latest and greatest testing methods to protect your health. Don't wait. Order a PHI test today and check out the hundreds of other testing options we offer. Your health is your greatest asset, and no one can protect it better than you.

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