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PSA Screen (SCPSA)

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EPIC Test Name

PSA SCREEN

EPIC Code

LAB2849

Specimen Requirements

plasma
Minimum Volume:0.5 mL
Collection:Collect using standard laboratory procedures
Transport:Room Temperature ASAP
Stability:Room Temperature : 24 hours at 20-25 degrees C
Refrigerated: 5 days at 2-8 degrees C
Frozen: 6 months at -20 degrees C
Container:LIT GRN
Processing/Storage:Centrifuge, pour off, and freeze plasma.
Rejection Causes:Hemolysis,
Insufficient Sample Volume
Notes:Samples should not be taken from patients receiving therapy with high biotin doses (i.e. > 5 mg/day) until at least 8 hours following the last biotin administration.

Methods

Immunoassay

Turnaround Time

SpecimenTurnaround TimeFrequency
plasma1 day24/7

Reference Ranges

Immunoassay
All RangeUnit
<4.0 ng/mLng/mL

Clinical Indications

Prostate Specific Antigen (PSA) is a 28-kDa glycoprotein of the prostate. PSA exists in the circulation as a free form and bound to protease inhibitors such as alpha 1-antichymotrypsin (ACT) and alpha 2-macroglobulin (A2M). Total PSA immunoassays cannot detect PSA-A2M due to that PSA is engulfed by the A2M and its antigenicity is not exposed.
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 PSA levels in the circulation. PSA is measured for the early detection of cancer, staging and monitoring responses of treatments. PSA is not specific to prostate cancer due to that PSA also increases in benign prostate diseases. To increase PSA clinical sensitivity and specificity, several approaches have been adopted. PSA for detecting cancer is increased when combined with digital rectal examination (DRE), noting that sample for PSA analysis must be collected prior to the DRE. Age-specific reference ranges are often adopted with lowering the upper limit of the reference range for younger men and raising the upper limit for older men. Usage of the molecular forms of PSA, i.e., free and total PSA (total = free + PSA bound to ACT), increases diagnostic accuracy and has been commonly adopted. Higher total PSA levels and lower percentages of free PSA are associated with higher risks of prostate cancer. The American Cancer Society recommends prostate cancer screening with PSA and DRE in men aged 50 and older. High risk occurs to patients with family history of prostate cancer and sub-Saharan African descent.

Additional Information

• Normal PSA values do not rule out the possibility of prostate cancer. Patient’s clinical presentation should always be considered.
• PSA test results obtained with different assay methods or kits can be different and must not be used interchangeably.
• PSA is not a specific marker for prostate cancer, therefore, results cannot be interpreted alone.
• Specimens collected from patients with performing procedure on the prostate, e.g., needle biopsy and transurethral resection, may have high PSA results that should not be used for clinical decisions. Blood samples should be obtained prior to the procedures.
• Cautions in interpreting PAS results should be given to patients receiving treatment. Prostate cancer treatments, e.g., antiandrogens and luteinizing hormone-releasing factor agonists, may cause markedly decreased PSA levels.
• Patients being treated for benign prostatic hyperplasia with inhibitors of 5-alpha-reductase (finasteride) may have a significant decreased PSA levels when compared to the values prior to the treatment.
• Patient samples with very high biotin concentrations > 1200 ng/mL as result of intake of biotin vitamin supplement may interfere with this assay. Samples should be redrawn on a different day after stopping taking the vitamin supplement.

Common Synonyms

Total Prostrate Specific Antigen Screen Total Prostate Specific Antigen Screen

Performed

Lab
Chemistry - Downtown

Interpretative Information

• In patients with total PSA values < 2.0 ng/mL, the probability of prostate cancer in asymptomatic men is low, additional testing and free PSA may not produce additional diagnostic information.
• In patients with total PSA values > 10.0 ng/mL, prostate cancer probability is high. Other tests are recommended, e.g., free PSA and prostate biopsy.
• In patients with a total PSA value within 4.0 - 10.0 ng/mL, or a diagnostic "gray zone" range, the ratio of free PSA to total PSA is helpful to in assessing the risk of prostate cancer and determining if undergoing biopsy procedure.
• It is noteworthy that a negative prostate biopsy result may not completely rule-out prostate cancer.

CPT

84153

LOINC

2857-1

References

1. Sokoll LJ, Chan DW. PSA: its discovery and biochemical chare teristics. Urol Clin North Am 1997;24:253-9.
2. Thompson IM, Goodman PJ, Tangen CM, Lucia MS, Miller GJ, Ford LG, et al. The influence of finasteride on the developmen d prostate cancer. N Engl J Med 2003;349:215-24.
3. Perin AV, Braver Mik, Bartsch G, Horninger W. Taneja SS, Lepor H, et al. Completed prostate specific antigen improves specificity for prostate cancer detection: results of a prospective multicenter clinical trial. J Urol 2003:170:1787-91.
4. Oesterling JE, Jacobsen SJ, Klee GG, et al: Free, complexed and total serum prostate specific antigen: the establishment of appropriate reference ranges for their concentrations and ratios. J Urol. 1995;154(3):1090-5. doi: 10.1016/s0022-5347(01)66984-2
5. Duffy MJ. Biomarkers for prostate cancer: prostate-specific antigen and beyond. Clin Chem Lab Med. 2020;58:326-9. doi: 10.1515/cclm-2019-0693
6. Catalona WJ: Prostate cancer screening. Med Clin North Am. 2018;102:199-214.
7. doi: 10.1016/j.mcna.2017.11.001

Contact Information

Chemistry - Downtown: (315)464-4460
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