Lab Test

Total Prostate Specific Antigen (tPSA)

PSA (Total), Prostate Specific Antigen, Total (tPSA)

Test Codes

Screening: EPIC: LAB5106, PSAS, Diagnostic: EPIC: LAB5105, PSAD

Department

Chemistry

Instructions

  • Prostate Specific Antigen, Screening, is restricted to one order per patient every 365 days.
  • Prostate Specific Antigen, Diagnostic, can be ordered as medically necessary.

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Contact the Laboratory for acceptability of other tube types.

Physician Office/Draw Specimen Preparation

Let SST specimens 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. (Minimum: 1.0 mL)

Preparation for Courier Transport

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

Rejection Criteria

  • Plasma specimens.
  • 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 and 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): 8 hours
Refrigerated (2-8°C or 36-46°F): 5 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): 8 hours
Refrigerated (2-8°C or 36-46°F): 5 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

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory
Wayne Chemistry Laboratory

Performed

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

Reference Range

Less than or equal to 2.50 ng/mL.

Test Methodology

Chemiluminescence Immunoassay.

Interpretation

  • Using a tPSA cut-off value of 4.00 ng/mL, one achieves a sensitivity of 78% and a specificity of 60% for cancer detection. Lowering the PSA threshold to 2.50 ng/mL may increase the rate of cancer detection in men younger than 60 years of age with little loss in specificity.
  • The Percent Free PSA (%fPSA) is one of five different approaches being used to improve the ability of PSA to detect early prostate cancer:
    1. Age-Specific Reference Ranges: The lab has not established age related cut-offs for our tPSA assay.
    2. tPSA Density: TPSA Serum value is divided by the prostatic volume determined by transrectal ultrasonography (TRUS). Patients with tPSA values between 4.00-10.00 ng/mL, negative digital rectal examination (DRE), and tPSA density greater than 0.15 have increased risk of prostate cancer.
    3. tPSA Velocity: A baseline tPSA value is established and the rate of increase of tPSA calculated. An average rate of 0.75 ng/mL/yr increased the specificity of tPSA to differentiate prostate cancer from BPH to 90%.
    4. Percent Free PSA: The %fPSA test order, which includes a tPSA, is performed only when the tPSA is between 2.5 and 10.00 ng/mL. Our research data suggests Beaumont patients with %fPSA values above 24% had a 1 in 10 chance of having a positive biopsy. Percent free PSA is a calculated value (fPSA/tPSA x 100).
    5. Percent Complexed PSA (%cPSA): Recent studies suggest:
      • For patients with a tPSA of 2.50-10.00 ng/mL, the %cPSA (greater than 76%) may improve the sensitivity of tPSA for prostate cancer detection and eliminate unnecessary biopsies.
      • For patients with a tPSA of 2.50-4.00 ng/mL, a cPSA cut-off of 2.20 ng/mL results in 92% sensitivity and 42% specificity for prostate cancer detection.

Clinical Utility

  • PSA is a serine protease (Kalikrein family) produced by epithelial cells of the acini and ducts of prostate gland. Normally, very little PSA is secreted into the blood. Increased PSA levels may be due to increases in glandular size and tissue damage caused by benign prostatic hypertrophy, prostatitits, and/or prostate cancer. The tPSA assay is used to monitor patients with a history of prostate cancer, both as an indicator of tumor recurrence and response to therapy.
  • The American Cancer Society recommends annual examination with digital rectal examination (DRE) and serum tPSA beginning at age 50 for men with a life expectancy of at least 10 years after detection, Men in a high risk group (African Americans) or those with strong familial predisposition, testing may begin at a younger age.

CPT Codes

Screening: G0103  Diagnostic: 84153.
LOINC: 35741-8

Contacts

Last Updated

6/15/2021

Microtainer® and Vacutainer® are registered trademarks of Becton, Dickinson and Company.
UroVysion® is a registered trademark of Abbott Laboratories. ThinPrep® is a registered trademark of Hologic, Incorporated.