Prostate Health Index

Overview

  • EPIC Code:
  • LAB3113
  • Soft Test Code:
  • PHI11
  • Send Out Test Code:
  • PHI11
Alternate Names
  • P2PSA
  • phi
  • phi score
  • Pro-2-PSA
  • Prostate Health Index (phi), Serum
Included Tests

Prostate Specific Antigen; Free Prostate Specific Antigen; p2PSA


Clinical Significance

Aids in distinguishing prostate cancer from benign prostate conditions in men with total prostate-specific antigen (PSA) concentrations in the 4 to 10 ng/mL range and digital rectal examination (DRE) findings that are not suspicious for cancer


Specimen Collection & Preparation

Patient Preparation

1. Specimens for testing should be drawn prior to prostate manipulations such as digital rectal examination (DRE), prostatic massage, transrectal ultrasound (TRUS), and prostatic biopsy.
2. Specimens should not be collected from patients receiving therapy with high biotin (vitamin B7) doses (ie, >5 mg/day) until at least 8 hours following the last biotin administration.


Specimen Requirements

1.0 mL Serum from a Red Top Tube in a Plastic Vial

 


Transport And Storage

150 days Frozen


Collection Instructions

Please Complete and send Phi Form with specimen 

Spin down within 3 hours of draw and separate serum from cells


Minimum Volume


Neonatal Volume

Clinical Interpretation

Reference Range:

TOTAL PROSTATE-SPECIFIC ANTIGEN (PSA)
 Males:
 Age
Reference Range
<40 years
< or =2.0 ng/mL
40-49 years
< or =2.5 ng/mL
50-59 years
< or =3.5 ng/mL
60-69 years
< or =4.5 ng/mL
70-79 years
< or =6.5 ng/mL
> or =80 years
< or =7.2 ng/mL

PERCENT FREE PSA
Males:
When total PSA is in the range of 4-10 ng/mL
% Free PSA
Probability of Cancer
< or =<10%
56%
11-15%
28%
16-20%
20%
21-25%
16%
>25%
8%

PROSTATE HEALTH INDEX (phi)
Males:
When total PSA is in the range of 4-10 ng/mL
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%
> or =55.0
50.1%
39.8-61.0%


Interpretation: 
Prostate health index (phi)may be used to determine the probability of prostate cancer on biopsy in men with total PSA in the 4 to 10 ng/mL range. Low phi scores are associated with a lower probability of finding prostate cancer on biopsy and higher phi scores are associated with an increased probability of finding prostate cancer on biopsy. The choice of an appropriate phi score to be used in guiding clinical decision-making may vary for each patient and may depend on other clinically factors or on family history of disease. The table below indicates the probability of finding prostate cancer on biopsy when PSA is the in range of 4 to 10 ng/mL and may be used as guidance for interpreting the phi score.
 
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%


Test Comments:

Testing Algorithm
This test begins with the analysis of prostate specific antigen (PSA). If the PSA is between 2.0 and 10.0 ng/mL, then the reflext test PHI13 will be performed

If the initial PSA is between 2.0 and 10.0 ng/mL, then free PSA and [-2] ProPSA will be reported.

If the initial PSA is between 4.0 and 10.0 ng/mL, then the percent free PSA and prostate health index (phi) will be calculated and reported.


Methodology:
  • Two-site Sandwich (Dual Mono)
Clinical Significance

Aids in distinguishing prostate cancer from benign prostate conditions in men with total prostate-specific antigen (PSA) concentrations in the 4 to 10 ng/mL range and digital rectal examination (DRE) findings that are not suspicious for cancer


Documentation

Prostate-specific antigen (PSA) is a glycoprotein produced by the prostate gland, the lining of the urethra, and the bulbourethral gland. Normally, very little PSA is secreted in the blood. In conditions of increase glandular size and/or tissue damage, PSA is released into circulation. Measurement of serum PSA is useful for determining the extent of prostate cancer and assessing the response to prostate cancer treatment. PSA is also used as a screening tool for prostate cancer detection, although its use in screening has become controversial in recent years. While an elevated serum PSA is associated with prostate cancer, a number of benign conditions, such as benign prostatic hyperplasia (BPH) and prostatitis might lead to elevated serum PSA concentrations. As a consequence PSA lacks specificity for prostate cancer detection. Several PSA isoforms have been identified that can further increase the specificity of PSA for prostate cancer. In particular, the [-2] form of proPSA (p2PSA) shows improved performance over either total or free PSA for prostate cancer detection on biopsy. The prostate health index (phi) is a formula that combines all 3 PSA forms (total PSA, free PSA, and p2PSA) into a single score. phi is calculated using the following formula: (p2PSA/free PSA) x square root (PSA). In a multicenter study that compared the performance of PSA, free PSA, p2PSA, and phi in men undergoing prostate biopsy due to a serum PSA concentration between 4 and 10 ng/mL, phi was the best predictor of any prostate cancer, high-grade cancer, and clinically significant cancer. At 95% clinical sensitivity, the clinical specificity of phi was 16.0%, compared to 8.4% for free PSA and 6.5% for PSA. Prostatic biopsy is required for diagnosis of cancer.


Production Schedule

Sites Performed
  • Mayo Laboratory
Days Performed
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Departments
  • Sendouts - Clinical
Turn Around Time

1 to 3 days


Coding & Compliance

CDM

00918707; 00918708; 00918706


CPT Coding

PSA (CPT 84153) - (Reflex freePSA (CPT 84154) and p2PSA (CPT 86316))