Sign in →

Epic Test Code LAB116 Prostatic Antigen (PSA), Total Screening

Performing Location(s)

BMC

Includes

Total PSA only (For information on requesting a Free PSA see “Prostatic Antigen (PSA) with Reflexive Free PSA, Screening” or “Prostatic Antigen (PSA) with Reflexive Free PSA, Monitoring”)

Specimen Type

Serum

Preferred Container

Gold or Red top tube

Blood Tube Draw Volume

Min 50% draw volume  

Minimum Volume to Submit for Testing

1 mL Serum

  • Multiple test can be performed from this volume. For question please contact the lab at 547-3975.  

 

Storage Requirements

*Does not need to be sent from outreach sites frozen, can be sent spun and refrigerated in primary tube

Sample tubes should be centrifuged within 2 hours of collection followed by transfer of the serum (red) to a labeled plastic, aliquot tube.

Gold tops do not need to be aliquoted
See Causes of Rejection for temperature requirements.

Transportation Needs

*Does not need to be sent from outreach sites frozen, can be sent spun and refrigerated in primary tube

 Deliver specimen to laboratory within 1 hour of collection if unspun. If not possible see "storage Requirements". 

Reference Values

Population Units Reference Range
Male ng/mL 0.1-4.0

 

Causes for Rejection

Mislabeled or unlabeled specimen
Less than 50% draw for Vacutainer tubes
> 5 months Refrigerated
> 3 hours Room Temperature
> 5 months Frozen
Hemolysis > 500 mg/dL HgB
Lipemia > 1500 mg/dL Trig
Bilirubin > 20 mg/dL Bili
EDTA,Heparin, NaF,Citrate, Oxalate
TP<4.2 or >12.1 g/dL



 

Additional Information

Prostate specific antigen (PSA) is a serine protease of approximately 30,000 Daltons produced by the epithelial cells of the prostate gland. The level of PSA in serum and other tissues is normally very low. In malignant prostate disease (prostatic adenocarcinoma) and in non-malignant disorders such as benign prostate hypertrophy (BPH) and prostatitis, the serum level of PSA may become elevated.

 

Most of the PSA protein in serum is complexed with either a1-antichymotrypsin (ACT) or a 2-macroglobulin.4,5 The PSA protein associated with a 2-macroglobulin is encapsulated and unavailable for measurement by current immunoassay systems. About 90% of the PSA in serum exists as PSA-ACT complex and 10% is free.
The PSA Screening assay measures both the free and the ACT bound components of serum PSA.

 

 

Important Information to consider when requesting Prostatic Antigen Testing

Limitations

The concentration of PSA in a given specimen determined with assays from different manufacturers can vary due to differences in assay methods and reagent specificity. Values obtained with different assay methods cannot be used interchangeably. If, in the course of monitoring a patient, the assay method used for determining serial PSA levels is changed, additional sequential testing should be carried out.
 

PSA levels may be lower in patients who receive hormonal therapy and may not adequately reflect the presence of residual or recurrent disease.

 

One step sandwich immunometric assays are susceptible to a high-dose “hook effect”, where an excess of antigen prevents simultaneous binding of the capture and detection antibodies to a single analyte molecule. The PSA method shows no hook effect up to 50,000 ng/mL[µg/L].
 

TPSA levels may be lower in patient who receive hormonal therapy and may not adequetly reflect residual or recurrent disease.

 

Patient samples may contain heterophilic antibodies that could react in immunoassays to give falsely elevated or depressed results. This assay has been designed to minimize interference from heterophilic antibodies, but complete elimination of this interferent is not guaranteed.

Free PSA is only stable for 24 hours at 4° Celsius. Total and Free PSA stable up to 3 freeze/thaw cycles.

Days of Analysis

All

Available STAT

No

Methodology

Beckman AU/Dx Series

CPT Code

84153 (HCPCS code: G0103)

Last Updated

29-NOV-24 MS