Home
HelpTest ID PSAFT Prostate-Specific Antigen (PSA), Total and Free, Serum
Useful For
The percentage of measured prostate-specific antigen (PSA) existing in the free form (free:total PSA ratio) is useful in assessing the risk of prostate cancer in patients with borderline or moderately increased total PSA (4.0-10.0 ng/mL) and has been used to help select men who should have follow-up prostate biopsy
Most prostate cancers are slow growing, so the utility of prostate cancer screening is marginal in most men with a life expectancy of <10 years.
Method Name
Electrochemiluminescent Immunoassay (ECLIA)
Reporting Name
PSA Total and Free, SSpecimen Type
SerumCollection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Spin down within 3 hours of draw and separate serum from cells.
Additional Information:
1. Free prostate-specific antigen (PSA) can only be added on within 12 hours of performing total PSA. Specimen must have been shipped frozen.
2. Include patient’s age.
3. 12 hours before this blood test do not take multivitamins or dietary supplements containing biotin or vitamin B7, which are commonly found in hair, skin and nail supplements and multivitamins.
Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)
Oncology Test Request Form (T729) (http://www.mayomedicallaboratories.com/it-mmfiles/oncology-request-form.pdf)
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen | 90 days |
Clinical Information
Prostate-specific antigen (PSA) is a glycoprotein that is produced by the prostate gland, the lining of the urethra, and the bulbourethral gland. Normally, very little PSA is secreted in the blood. Increases in glandular size and tissue damage caused by benign prostatic hypertrophy, prostatitis, or prostate cancer may increase circulating PSA levels.
PSA exists in serum in multiple forms: complexed to alpha-1-anti-chymotrypsin (PSA-ACT complex), unbound (free PSA), and enveloped by alpha-2-macroglobulin (not detected by immunoassays).
Higher total PSA levels and lower percentages of free PSA are associated with higher risks of prostate cancer.
Reference Values
TOTAL PSA
Males:
|
Age (Years) |
PSA Upper Limit (ng/mL) |
|
<40 |
≤2.0 |
|
40-49 |
≤2.5 |
|
50-59 |
≤3.5 |
|
60-69 |
≤4.5 |
|
70-79 |
≤6.5 |
|
≥80 |
≤7.2 |
Females: not applicable
FREE PSA
Males: When total PSA is in the range of 4.0-10.0 ng/mL, a free:total PSA ratio ≤0.10 indicates 49% to 65% risk of prostate cancer depending on age; a free:total PSA ratio >0.25 indicates a 9% to 16% risk of prostate cancer, depending on age.
Females: not applicable
Cautions
Twelve hours before this blood test do not take multivitamins or dietary supplements containing biotin or vitamin B7, which are commonly found in hair, skin, and nail supplements and multvitamins.
Normal results do not eliminate the possibility of prostate cancer.
Values obtained with different assay methods or kits may be different and cannot be used interchangeably.
Tumor markers are not specific for malignancy. Test results cannot be interpreted as absolute evidence for the presence or absence of malignant disease.
Specimens drawn from patients undergoing prostate manipulation, especially needle biopsy and transurethral resection, may show erroneously high prostate-specific antigen (PSA) results. Care should be taken that specimens are drawn before these procedures are performed.
Prostate cancer patients receiving treatment with antiandrogens and luteinizing hormone-releasing factor agonists may exhibit markedly decreased levels of PSA. Also, men treated for benign prostatic hyperplasia with inhibitors of 5-alpha-reductase (finasteride) may demonstrate a significant reduction in PSA levels compared to values before treatment. Care should be taken in interpreting values for these individuals.
In rare cases, interference due to extremely high titers of antibodies to ruthenium or streptavidin can occur.
Day(s) Performed
Monday through Friday; 5 a.m.-12 a.m., Saturday; 6 a.m.-6 p.m.
Report Available
1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. 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
84154-Free