Prostate Health Index Reflex, Serum
Use
The Prostate Health Index (phi) is used 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, with digital rectal examination findings that are not suspicious for cancer. Phi may determine the probability of prostate cancer on biopsy for those with total PSA in this range. The calculated phi score aids in clinical decision-making by providing probability of finding prostate cancer, with lower scores associated with decreased probability.
Special Instructions
Specimens should be collected prior to prostate manipulations such as digital rectal examination, prostatic massage, transrectal ultrasound, and prostatic biopsy. A 6-week waiting period is recommended between a needle biopsy and specimen collection. Specimens should also not be collected from patients on high biotin doses (>5 mg/day) until 8 hours after the last dose. Use the Oncology Test Request forms when ordering manually.
Limitations
Prostate health index results should be interpreted considering clinical presentation, including symptoms, clinical history, data from additional tests, and other relevant information. Phi should not be interpreted as definitive evidence for the presence or absence of prostate cancer. Increases or decreases in PSA, free PSA, and phi levels can occur due to benign prostatic conditions. Interference from various sources such as elevated total protein, biotin supplementation, or heterophile antibodies can affect phi and its components. Routine use of 5 alpha-reductase inhibitors may lower PSA, free PSA, and p2PSA levels.
New York Approved
Methodology
Immunoassay (Immunoenzymatic Assay)
Biomarkers
LOINC Codes
- 53764-7
- 83112-3
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.75 mL
Container
Red top (serum gel/SST are not acceptable); Submission: Plastic vial
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.
Patient Preparation
Specimens should be collected prior to prostate manipulations such as digital rectal examination, prostatic massage, transrectal ultrasound, and prostatic biopsy. Patients on high biotin doses (>5 mg/day) should wait at least 8 hours after last dose before collection.
Causes for Rejection
Gross hemolysis or gross icterus specimens will be rejected.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 24 hours |
| Frozen | 150 days |