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HelpTest Code P2PHI [-2]Pro Prostate-Specific Antigen with Prostate Health Index, Serum
Specimen Required
Patient Preparation:
1. Specimens for testing should be collected prior to prostate manipulations such as digital rectal examination (DRE), prostatic massage, transrectal ultrasound (TRUS), and prostatic biopsy.
2. A 6-week waiting period between needle biopsy and specimen collection is recommended.
3. 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.
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Within 3 hours of collection, centrifuge, aliquot serum into a plastic vial, and refrigerate. Freeze sample within 24 hours of collection and send frozen.
Secondary ID
608462Useful For
As an aid in distinguishing prostate cancer from benign prostatic conditions in men aged 50 years and older with total PSA between 4.0 and 10.0 ng/mL and digital rectal examination findings that are not suspicious for cancer.
Method Name
Immunoenzymatic Assay
Reporting Name
p2PSA with Prostate Health Index, SSpecimen Type
Serum RedSpecimen Minimum Volume
0.75 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen (preferred) | 150 days | |
| Ambient | 24 hours | ||
| Refrigerated | 24 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross icterus | Reject |
Clinical Information
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 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 total 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 total PSA.
Reference Values
Females: Not applicable
PROSTATE-SPECIFIC ANTIGEN (PSA) MALES:
|
Age |
Reference range |
|
<40 Years |
≤2.0 ng/mL |
|
40-49 Years |
≤2.5 ng/mL |
|
50-59 Years |
≤3.5 ng/mL |
|
60-69 Years |
≤4.5 ng/mL |
|
70-79 Years |
≤6.5 ng/mL |
|
≥80 Years |
≤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 |
|
≤10% |
56% |
|
11-15% |
28% |
|
16-20% |
20% |
|
21-25% |
16% |
|
>25% |
8% |
PROSTATE HEALTH INDEX (phi) MALES:
When 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% |
|
≥55.0 |
50.1% |
39.8-61.0% |
Interpretation
The prostate health index (phi) may be used to determine the probability of prostate cancer on biopsy in men 50 years of age and older with total prostate-specific antigen (PSA) in the 4.0 to 10.0 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 clinical factors or family history. The table below indicates the probability of finding prostate cancer on biopsy when total PSA is in the range of 4.0 to 10.0 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% |
Specimen Retention Time
2 weeksPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84153-Total PSA
84154-Free PSA
86316-[-2]ProPSA
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| P2PHI | p2PSA with Prostate Health Index, S | 53764-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| PSAT | Prostate Specific Antigen, S | 83112-3 |
| PSAF | Free PSA, S | 83113-1 |
| PSAP2 | [-2]ProPSA, S | 97149-9 |
| PSAP3 | % Free PSA | 12841-3 |
| PSAP4 | Prostate Health Index | 97150-7 |
Day(s) Performed
Monday through Saturday