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Free PSA (including Total)

Test Codes

EPIC: LAB2111152, PSAF2; For men 49 and younger go to: EPIC: LAB1231739

Department

Toxicology

Instructions

Only performed on male patients at birth, and who are 50 and older.

Free PSA (including Total PSA  and % Free PSA) will only be performed when Total PSA is between 4.0 and 10.0 ng/mL.

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)

Contact the Laboratory for acceptability of other tube types.

Physician Office/Draw Specimen Preparation

Let SST specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection.

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 1.0 mL)

Rejection Criteria

• Plasma specimens.
• Severely hemolyzed specimens.
• Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes or Microtainers^® to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-25°C or 68-77°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Automated Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Results available within 24 hours of receipt in the Laboratory.

Reference Range

Total PSA (tPSA): Less than or equal to 4.0 ng/mL.
Free PSA (fPSA): Not established.
% Free PSA: Greater than or equal to 24%.

Test Methodology

Chemiluminescence Immunoassay.

Interpretation

The % fPSA test order includes a Total PSA. The fPSA will be performed only when the tPSA is between 2.5 and 10 ng/mL.

When total PSA is in the range of 2.5 to 10 ng/mL, the percent (%) Free PSA gives an estimate of the probability of cancer.  A % Free PSA of < = 10% indicates a 49% to 65% risk of prostate cancer, depending on age; a % Free PSA of > 25% indicates a 9% to 16% risk of prostate cancer, depending on age (JAMA 1998; 279: 1542 – 1547).

In these circumstances the measurement of % Free PSA may aid in avoiding unnecessary biopsies.  The ultimate decision to perform prostate biopsy should be made between the patient and clinician, based on all relevant clinical and laboratory findings.

Clinical Utility

The % fPSA is used to determine the risk of prostate cancer.

Recent studies have suggested that fPSA testing may improve the sensitivity of the PSA test for prostate cancer detection and can minimize unnecessary prostate biopsies in patients with tPSA values between 2.5 and 10 ng/mL. The ultimate decision to perform prostate biopsy should be made by the clinician, based on all relevant clinical and laboratory findings.

Elevated levels of Prostate Specific Antigen (PSA) have been associated with benign and malignant prostatic disorders. Studies indicate that in men 50 years or older measurement of PSA is a useful addition to the digital rectal exam in the early detection of prostate cancer. In addition, PSA decreases to undetectable levels following complete resection of the tumor and may rise again with recurrent disease or persist with residual disease. Thus, PSA levels may be of assistance in the management of prostate cancer patients.

CPT Codes

84153, 84154.
LOINC: 10886-0, % Free 12841-3

Contacts

Last Updated

8/19/2024