PHI tests measure three blood markers related to prostate-specific antigen (PSA): total PSA, free PSA, and the [-2]proPSA (p2PSA) isoform. These values are combined into a calculated Prostate Health Index (commonly given by PHI = ([-2]proPSA / free PSA) × √(total PSA)), producing a single score that correlates with the probability of prostate cancer—especially clinically significant disease—better than total PSA alone.

PHI is an indicator used to help decide whether further evaluation (such as biopsy or imaging) is warranted; higher PHI scores indicate a higher likelihood of prostate cancer, while lower scores suggest a lower likelihood. It is not by itself diagnostic and should be interpreted alongside clinical exam, imaging, and other risk factors.

A PHI sample is collected by a routine blood draw (venipuncture), usually from a vein in your arm, performed by a trained phlebotomist at a clinic or laboratory; the blood is placed into standard collection tubes and sent to the testing lab.

In the lab total PSA, free PSA and [-2]proPSA (p2PSA) are measured and combined to calculate the Prostate Health Index (PHI) using the established formula (p2PSA ÷ free PSA) × √(total PSA), producing a single score used as an indicator of prostate cancer risk.

Your Prostate Health Index (PHI) combines measurements of total PSA, free PSA, and [-2]proPSA into a single score that reflects the probability of clinically significant prostate cancer: lower PHI scores generally indicate a lower likelihood of finding cancer on biopsy, while higher scores indicate a higher likelihood. PHI is a risk‑stratification tool—not a diagnosis—so it estimates probability rather than confirming or ruling out cancer.

PHI is most useful when considered with other information (age, family history, digital rectal exam, prostate volume, prior test results) to guide decisions about monitoring versus further testing such as imaging or biopsy. Exact cutoffs and recommended actions vary by lab and clinician, so use your PHI result as one piece of information and follow your healthcare provider’s interpretation and recommendations.

The Prostate Health Index (PHI) combines total PSA, free PSA and [-2]proPSA into a single score and has been shown to be more accurate than total PSA alone for discriminating prostate cancer from benign causes. In clinical studies PHI usually improves specificity and overall discrimination (area under the ROC curve commonly reported in the ~0.7–0.8 range), and it is particularly better at identifying men at higher risk of clinically significant (higher‑grade) cancer—so it can help reduce unnecessary biopsies compared with using total PSA alone.

PHI is not a diagnostic test by itself: it produces false positives and false negatives, and performance depends on the chosen cutoff, patient population and clinical context. Results can be affected by prostatitis, recent procedures and some medications. PHI should be interpreted together with clinical exam, patient risk factors and other tests (for example mpMRI) — an abnormal PHI often prompts biopsy, while a low PHI lowers but does not eliminate the possibility of clinically important cancer.

Testing frequency for Prostate Health Index (PHI) depends on individual risk factors and prior results: for men with a low, stable PHI and no other concerning findings, testing every 12–24 months is often reasonable; for those with borderline or elevated PHI, a rising trend, abnormal PSA, suspicious exam, or a prior negative biopsy with ongoing concern, repeat testing every 3–6 months may be appropriate to decide on further evaluation.

PHI is one part of prostate assessment and should be interpreted alongside PSA trends, digital rectal exam, imaging, and clinical context—follow-up intervals should be determined with your clinician based on age, family history, symptoms, and overall risk, and adjusted if results change.

No, Prostate Health Index (PHI) test results highlight patterns of imbalance or resilience—not medical diagnoses. They should be interpreted alongside symptoms, medical history, and other lab or biomarker data by a qualified clinician.

PHI is a lab marker that reflects PSA biology and prostate health; short‑term steps that often lower PSA/PHI before a repeat test include avoiding ejaculation and vigorous cycling or heavy pelvic-impact exercise for ~48–72 hours, postponing any prostate manipulation or urinary procedures, and treating any suspected urinary tract infection or prostatitis under a clinician’s care (antibiotics/anti‑inflammatories when indicated can reduce inflammation-related PSA elevation).

For longer‑term changes, focus on general health measures—maintain a healthy weight, engage in regular aerobic and resistance exercise, eat a balanced (Mediterranean‑style) diet rich in vegetables and low in processed/red meats, control diabetes/metabolic syndrome, limit alcohol, and stop smoking—which may lower chronic inflammation and improve prostate health. Do not start, stop or change prescription medications (including 5‑alpha‑reductase inhibitors that alter PSA) without discussing with your urologist, and arrange follow‑up testing and clinical evaluation because PHI reflects risk rather than a modifiable guarantee; treatment and monitoring decisions should be made with your clinician.