Prostate Health Index (phi) Profile*

Use: The Access Hybritech PSA assay is indicated for the measurement of serum PSA in conjunction with digital rectal examination (DRE) as an aid in the detection of prostate cancer in men aged 50 year or older.1 This test is further indicated for the serial measurement of PSA to aid in the prognosis and management of patients with prostate cancer.

The Access Hybritech free PSA assay is intended to be used with Hybritech (total) PSA to calculate the ratio of free PSA to total PSA expressed as a percentage (percent free PSA).2 Percent free PSA as measured by the Hybritech assays is indicated for use as an aid in distinguishing prostate cancer from benign prostatic conditions, when used in conjunction with Hybritech (total) PSA for prostate cancer detection in men aged 50 years and older with total PSA between 4 and 10 ng/mL (using Beckman Hybritech calibration) with digital rectal examination findings that are not suspicious for cancer.

The Prostate Health Index (phi) as calculated using the Beckman Coulter Access Hybritech assays is indicated for use as an aid in distinguishing prostate cancer from benign prostatic conditions, for prostate cancer detection in men aged 50 years and older with total PSA ≥4.0 to ≤10.0 ng/mL, and with digital rectal examination findings that are not suspicious for cancer.3

Prostatic biopsy is required for diagnosis of cancer.

Limitations: The concentration of fPSA and PSA in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods and reagent specificity.1,2 PSA concentrations are dependent on the standard used to calibrate the assay. Values obtained with different manufacturers' assays cannot be used interchangeably. If, in the course of monitoring a patient, the assay method used for determining PSA levels serially is changed, additional sequential testing should be carried out to confirm baseline values.

PSA concentrations based on calibration to the WHO 96/670 Reference Preparation will differ significantly from PSA concentrations based on calibration to the original Hybritech Tandem-R assay.

Beckman Access Hybritech p2PSA should be used only with Beckman Access Hybritech PSA and Beckman Access Hybritech free PSA to calculate the Beckman Coulter phi. Use of another manufacturer's PSA and/or free PSA (fPSA) assays may result in:

• Selection of an inappropriate population of patients for follow-up testing.

• Significantly different cutoffs and cancer probabilities than those presented in the Expected Values section.

Expected values apply only to Beckman Coulter phi as measured by the Access Hybritech PSA free PSA, and [-2]proPSA (p2PSA) assays.

The Beckman Coulter phi results should be interpreted in light of the total clinical presentation of the patient, including symptoms, clinical history, data from additional tests and other appropriate information. Beckman Coulter phi should not be interpreted as absolute evidence for the presence or absence of prostate cancer. Elevated PSA concentrations, increased Beckman Coulter phi, or decreased %fPSA (ratio of fPSA to PSA) may be observed in the serum of patients with non-malignant disorders, as well as those with prostate cancer. Furthermore, low PSA concentrations, low Beckman Coulter phi, or elevated %fPSA (ratio of fPSA to PSA) are not necessarily indicative of the absence of cancer.

Serum PSA, fPSA, p2PSA and values should be used in conjunction with information available from the clinical evaluation of the patient and other diagnostic procedures as digital rectal examination (DRE). Some cases of early prostate cancer will not be detected by PSA testing; the same is true for DRE. Biopsy of the prostate is the standard method used to confirm the presence or absence of prostate cancer.

Routine use of 5 alpha-reductase inhibitor drugs typically lower PSA, fPSA and p2PSA levels in patients. Other drugs used to treat benign prostatic hyperplasia (BPH) may also affect PSA levels. Care should be taken in interpreting results from patients taking these drugs.

For assays employing antibodies, the possibility exists for interference by heterophile antibodies in the patient sample. Patients who have been regularly exposed to animals or have received immunotherapy or diagnostic procedures utilizing immunoglobulins or immunoglobulin fragments may produce antibodies, e.g., HAMA, that interfere with immunoassays. Additionally, other heterophile antibodies such as human anti-goat antibodies may be present in patient samples.4,5 Such interfering antibodies may cause erroneous results. Carefully evaluate the results of patients suspected of having these antibodies.

For patient samples containing elevated levels of total protein (>8 g/dL), the possibility exists for interference by total protein. Carefully evaluate the results of patients suspected of having elevated total protein levels.

Beckman Coulter phi values should not be interpreted as definitive evidence for the presence or absence of prostate cancer. Prostatic biopsy is required for diagnosis of cancer.

Methodology: PSA and fPSA concentrations are dependent on the standard used to calibrate the assays. PSA and fPSA concentrations reported by Labcorp for this assay are based on the Beckman Coulter Hybritech calibration standards.6 It should be noted that a PSA range of 4 to 10 ng/mL using Hybritech calibration corresponds to a PSA range of 3.1 to 7.8 ng/mL using WHO calibration. The Beckman Coulter phi scores will also be different if the PSA and free PSA tests used to derive the Beckman Coulter phi score were WHO-calibrated. Beckman Access Hybritech PSA, fPSA and p2PSA are performed and used to calculate the Beckman Coulter phi.

Reference Interval: Total PSA: 0.0–3.9 ng/mL