Prostate-Specific Antigen (PSA), Total

Label Mnemonic:	PSA
Epic code:	LAB116
Downtime form:	Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Chemistry
6240 RCP
356-3527

Specimen(s):

Plasma

Collection Medium:

Plasma Separator Tube 4.5 mL

Alternate Collection Media:

Call laboratory for additional acceptable specimen collection containers.

Minimum:

3 mL whole blood in light green top tube or TWO Microtainer^® devices.

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Turn Around Time:

1 hour (upon receipt in laboratory)

Reference Range:

   Age     Reference Range
Up to 50   0.00-2.50 ng/mL
50 - 59    0.00-3.50 ng/mL
60 - 69    0.00-4.50 ng/mL
> 70       0.00-6.50 ng/mL

Age specific normal values from the literature for PSA are provided as 
a guide only.  No one decision level is appropriate when utilizing PSA 
in screening situation.  Age, family history, previous values, and 
other factors should be used in decisions involving PSA values.

Comments:

Assay updated with increased tolerance to biotin on 11/9/21.

Prostate-Specific Antigen (PSA) measurement used in conjunction with Digital Rectal Exam (DRE) is indicated as an aid for the detection of prostate cancer in men aged 50 years or older. It is also useful in monitoring patients with known prostate cancer. PSA is specific to the prostate gland and is present in normal, hyperplastic and neoplastic prostatic epithelium. Serum elevations are detected in not only prostate carcinoma, but also in benign prostatic hypertrophy and inflammatory conditions of the prostate and adjacent genitourinary tissues. Diagnosis of prostate cancer requires biopsy and histopathologic examination.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).

Test Limitations:

The assay is unaffected by icterus (bilirubin < 65 mg/dL),
hemolysis (Hb is less than 2200 mg/dL), lipemia (Intralipid is less
than 1500 mg/dL) and biotin is less than 1200 ng/mL (criterion: recovery within plus or minus 10% of initial value).

No interference was observed from rheumatoid factor (up to 1,500
IU/mL).

There is no high-dose hook effect at tPSA concentrations up to 17,000
ng/mL.

In vitro tests were performed on 28 commonly used pharmaceuticals. No
interference with the assay was found.

As with all tests containing monoclonal mouse antibodies, erroneous
findings may be obtained from samples taken from patients who have
been treated with monoclonal mouse antibodies or have received them
for diagnostic purposes. Elecsys total PSA contains additives which
minimize these effects.

In rare cases, interference due to extremely high titers of antibodies
to streptavidin can occur.

It is known that in rare cases PSA isoforms do exist which may be
measured differently by different PSA tests. Findings of this kind
have occasionally been reported for PSA tests from various
manufacturers.(1-3)

For diagnostic purposes, the total PSA findings should always be
assessed in conjunction with the patient's medical history, clinical
examination and other findings.

(1) Van Duijnhoven HLP, Perqueriauz NCV, van Zon JPHM, Blankenstein MA.
Large discrepancy between prostate specific antigen results from
different assays during longitudinal followup of a prostate cancer
patient. Clin Chem 1996;42:637-641.

(2) Wians FH. The "Correct" PSA Concentration. Clin Chem
1996;42:1882-1885

(3) Cohen RJ, Haffejee Z, Steele GS, Nayler SJ. Advanced Prostate
Cancer With Normal Serum Prostate-Specific Antigen Values. Arch
Pathol Lab Med 1994;118:1123-1126.

Methodology:

Electrochemiluminescence Immunoassay

CPT Code:

84153