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Prostate Health Index (phi)

An FDA-approved blood test to be used as an aid in distinguishing prostate cancer from benign prostatic conditions1

The Prostate Health Index (phi) is a calculation that uses a combination of three blood tests to produce a "phi score." This score provides more information about what elevated PSA levels might mean and the probability of finding prostate cancer on biopsy.*

This product may not be available in your country at this time. Please contact your Beckman Coulter sales representative or distributor for more information.

What is phi?

  • A simple blood test to improve early detection of prostate cancer
  • A tool to reduce negative biopsies and provide more confidence in your biopsy decisions
  • A recommendation by the National Comprehensive Cancer Network (NCCN) Guidelines for PCa Early Detection prior to transrectal ultrasound (TRUS) guided biopsies

phi comprises three tests in combination:

  • PSA
  • free PSA
  • p2PSA

The new p2PSA assay specifically measures [-2]proPSA. The [-2]proPSA biomarker is an isoform of free PSA that was identified as the most prostate cancer-specific form found in tumor extracts.The PSA, free PSA and p2PSA results are combined in the Access instrument to calculate a probability of prostate cancer.

Benefits of phi

The PSA test is a widely used screening tool for prostate cancer. However, given the PSA test's limited specificity for cancer, a more precise tool is needed for prostate cancer detection. The phi score provides better risk stratification to identify patients who need a biopsy.* The appropriate use of phi can significantly modify physicians' behavior patterns and improve their ability to diagnose and manage their patients. phi is another tool to help physicians and help their patients decide if a biopsy is right for them.2

The power of phi

A recent study published in Prostate Cancer and Prostatic Diseases demonstrated that physicians elected to perform fewer prostate biopsies for men who presented in the diagnostic gray zone when phi testing was included in their overall routine clinical assessment. Physicians reported that phi testing significantly impacted their patient management decision in over 73% of their cases. Only 36% of men received biopsies when phi testing was included in the assessment, compared with the 60% who had to undergo such procedures before phi was available.2 

More than 80 published clinical papers and meeting abstracts demonstrate the health benefits and economic value of phi

How is phi used in clinical practice?

Because phi improves specificity for prostate cancer, it fills the diagnostic gap between PSA screening and a prostate biopsy (Figure 1). 

Figure 1. Diagnostic Considerations for Prostate Cancer
phi infographic showing how phi bridges the diagnostic gap between PSA test and the decision between monitoring or prostate biopsy

phi fills the diagnostic gap between PSA screening and a prostate biopsy.


What does the phi score mean?

Table 1 represents clinical study data analyzed to estimate an individual patient's probability of having detectable prostate cancer based on Beckman Coulter phi results when that patient has a PSA in the diagnostic gray zone between 4 and 10 ng/mL.3 At phi cutoffs between 27 to 55, the probability of cancer ranged from 16.8 to 50.1%. For example, a patient with a phi result below 27 has a 90% chance that his prostate biopsy will be negative.

Table 1. Probability of Prostate Cancer Based on phi Results Between 4 and 10 ng/mL1

phi Range* Probability of Cancer 95% Confidence Interval
 0–26.9  9.8%  5.2%–15.4%
 27.0–35.9  16.8%  11.3%–22.2%
 36.0–54.9  33.3%  26.8%–39.9%
 55.0+  50.1%  39.8%–61.0%

Clinical study data shows phi results can be used to assess probability of cancer.

The phi diagnostic gray zone in countries outside of the U.S. is defined as PSA levels between 2 and 10ng/mL. The probability slightly changes based on these PSA levels (see Table 2).

Table 2. Probability of Prostate Cancer Based on phi Results Between 2 and 10 ng/mL2

(Hybritech Calibration of PSA and free PSA)
Beckman Coulter phi Range*
(Hybritech Calibration)
Probability of Cancer 95% Confidence Interval
0–21 8.4% 1.9%–16.1%
21–40 21.0% 17.3%–24.6%
40+ 44.0% 36.0%–52.9%

Clinical study data shows phi results can be used to assess probability of cancer.

 

Bringing phi to your physicians and patients

phi is exclusive to Beckman Coulter and therefore must be run on a Beckman Coulter immunoassay analyzer. If your laboratory includes a Beckman Coulter analyzer, it's easy to get the laboratory set up to run these tests. 

Interested in trying phi before you bring it in-house?

If you do not have a Beckman Coulter immunoassay analyzer to run phi, consider sending out to one of our reference laboratories below.

  • Mayo Medical Laboratories is a global reference laboratory operating within Mayo Clinic’s Department of Laboratory Medicine and Pathology that offers more than 3,000 tests across all healthcare sub-specialties. It is certified by CAP and CLIA and its quality programs exceed the high level of proficiency and standardization that auditors require. Mayo Medical Laboratories offers the FDA-approved phi test in all 50 states, as well as internationally. www.MayoMedicalLaboratories.com/phi-test. Phone number: 855.516.8404
  • ACCU Reference is a state-of-the-art, multi-specialty medical laboratory that provides the complete range of tests for diagnostics, screening and evaluation of various health conditions. Information provided by ACCU Reference helps clinicians improve the quality of care by confirming diagnoses of medical conditions, directing therapy and predicting patients' health risks. Strategic partnership with ACCU Reference prevents excessive utilization of medical procedures, ultimately promoting appropriate and cost-effective medical management. ACCU Reference is dedicated to delivering world-class service to physicians, medical centers, hospitals and their patients. www.accureference.com/phi/. ACCU Reference Medical Lab's dedicated phi Phone number: 800.766.8378. Disclaimer: ACCU Reference is only available to U.S. customers
  • Lenco Diagnostic Laboratory is a fully licensed facility by the state of New York, New Jersey and Pennsylvania and is certified by CLIA and CAP. Providing diagnostic testing and monitoring services, Lenco Diagnostic Laboratory is noted for its expertise in infectious diseases, immunology, rheumatology, oncology, neurology, nephrology, gastroenterology, obstetrics/gynecology, genetics and endocrinology. www.lencolab.com. Phone number: 718.232.1515. Email: tatyana@lencolab.com
  • Innovative Diagnostic Laboratory is a national clinical reference lab specializing in personalized blood-based testing to help find, understand and address cancer risk in patient populations. www.myinnovativelab.com. Phone number: 855.420.7140

Frequently asked questions

Q: Is phi (p2PSA) FDA approved?
A: Yes, phi (p2PSA) received FDA approval in June 2012. 

Q: Is phi in the National Comprehensive Cancer Network (NCCN) Guidelines?
A: Yes, phi was first added to the NCCN Guidelines in 2014. 

Q: Are there any clinical studies on phi available?
A: Yes, there are more than 80 published studies on phi from around the world. Your Beckman Coulter representative can provide a summary of these clinical studies. 

Q: Do you have to run Beckman Coulter's PSA and fPSA assays to calculate phi
A: Yes, phi is calculated using the test results from Beckman Coulter's PSA, fPSA and p2PSA, all using the same method of calibration. 

Q: Is phi reimbursed? 
A: CPT coding for reporting the calculation of phi is similar to coding for reporting the calculation of %free PSA. For %free PSA, laboratories have billed for both the PSA and free PSA tests when reporting %free PSA results. For phi, three national organizations (American Urology Association; PRS Urology; CodeMap of Wheaton Partners, LLC) have all recommended that, when reporting phi results, laboratories should bill for the PSA (CPT 84153), free PSA (CPT 84154), and p2PSA (CPT 86316) tests. All three CPT codes within the recommendations are listed on the Medicare Clinical Lab Fee Schedule. 

For additional information or a copy of the recommendations, please contact the Beckman Coulter Reimbursement Hotline at 800.396.2159.

Q: Is phi positioned as a first-line repeat/confirm PSA or as a reflex after PSA is confirmed and in the 410 ng/mL range? 
A: phi labeling indicates it should be run after confirmation that PSA is in the 410 ng/mL range. This indication extends to both initial and repeat biopsies.

PSA, fPSA and p2PSA assay specifications

The table below summarizes a few key specifications and performance indicators of each assay.

PSA

free PSA

p2PSA

Two-site Sandwich
(Dual Mono)
Two-site Sandwich
(Dual Mono)
Two-site Sandwich
(Dual Mono)
Serum Serum Serum
25 µL 25 µL 50 µL
<0.008 ng/mL*
(analytical)
<0.005 ng/mL
(analytical)
0.50 pg/mL (LoB)
3.23 pg/mL (LoQ) 
0.69 pg/mL (LoD)
Hybritech: 0.008-150 ng/mL 
WHO: 0.008-121 ng/mL
Hybritech: 0.005-20 ng/mL 
WHO: 0.005-16 ng/mL
0.50-5000 pg/mL
≤7% at >1.4 ng/mL 
≤0.1 ng/mL SD at ≤1.4 ng/mL
<7% <20% at 3.23 to 10 pg/mL 
≤10% at ≥10 pg/mL
20 min. 20 min. 22 min.

 

 

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Brochure The phi Clinical Summary

The superior performance of phi compared to PSA alone has been demonstrated through multiple peer-reviewed publications. Read summaries of the articles and discover the power of phi.

Download

1Loeb S, Sanda MG, Broyles DL, et al. The prostate health index selectively identifies clinically significant prostate cancer. J Urol, 2015; 193(4):1163-9.

2Jay White B, Vittal Shenoy, et al. Clinical utility of the Prostate Health Index (phi) for biopsy decision management in a large group urology practice setting. Prostate Cancer and Prostatic Diseases. https://doi.org/10.1038/s41391-017-0008-7. 

3Beckman Coulter Access Hybritech p2PSA Instructions for Use.

*phi results are intended to be used as an aid in distinguishing prostate cancer from benign prostatic conditions in men 50 years of age and older with total PSA results in the 4-10 ng/mL range and negative digital rectal examination DRE findings.

Biopsy outcomes of patients in the 4-10 ng/mL range.

Indicated for use as an aid in distinguishing prostate cancer from benign prostatic conditions in men aged 50 years and older with total PSA results in the 4-10 ng/mL in the U.S and or the 2-10 ng/mL range outside the U.S.