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Interpretive Handbook

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Test 57486 :
PCA3 Assay

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Background: PCA3 is a non-coding prostate-specific mRNA that is highly over-expressed in some prostate cancer cells (median 66-fold over adjacent benign tissue); in contrast. PSA gene expression is similar in benign and malignant prostate cells. Both PCA3 and PSA mRNA can be quantitated from urine samples. The PCA3 assay utilizes voided urine collected following a digital rectal examination and processed by addition into a urine transport medium (UTM) which lyses cells and stabilizes RNA. The PSA mRNA level serves to confirm that there is sufficient prostate RNA for analysis present in the sample and to normalize the PCA3 mRNA signal. In a study of 466 patients with previous negative prostate biopsy, 102 of whom had a positive follow-up biopsy, utilizing the PCA3 score cutoff value of 25 was shown to have 77.5% sensitivity and 57.1% specificity for prostate cancer. This assay is indicated for use in conjunction with other patient information to aid in the decision of repeat biopsy in men 50 years of age or older who have had one or more previous negative prostate biopsies and for whom a repeat biopsy would be recommended by a urologist based on current standard of care, before consideration of the PCA3 assay results. This assay should not be used for men with atypical small acinar proliferation (ASAP) on their most recent biopsy; men with ASAP on their most recent biopsy should be treated in accordance with current medical guidelines.

 

PCA3 score interval

Number of subjects

Percent of subjects

with Positive Biopsy

<12

114

10%

12-<25

117

12%

25-<47

116

28%

47+

119

35%

This figure shows the percentage of subjects with positive biopsy results by PCA3 score interval.

 

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Reference Range:          

        <25 negative

> or = 25 positive

 

Comment: Due to normal assay variability, specimens with PCA3 scores near the cut-off of 25 (i.e. 18-31) could yield a different overall interpretation of positive or negative upon repeat testing. PCA3 scores in the range from 18 to 31 should, therefore, be interpreted with caution.

 

The testing method is target capture, transcription-mediated amplification (TMA) and hybrid protection assay (HPA), manufactured by Gen-Probe and performed using the Gen-Probe PROGENSA assay kit.

 

Test Performed by: DIANON Systems, Inc.

                             1 Forest Parkway

                             Shelton, CT 06484

Clinical References Provides recommendations for further in-depth reading of a clinical nature

Aubin SM et al. 2010. PCA3 molecular urine test for predicting repeat prostate biopsy outcome in populations at risk: validation in the placebo arm of the dutasterid REDUCE trial. Urology. 184:1947-1952.

 

Mark LS et al. 2007. PCA3 molecular urine assay for prostate cancer in men undergoing repeat biopsy. Urology. 44:8-16.

 

PROGENSA PCA3 Assay Package Insert 502083 Rev. A. Gen-Probe Incorporated.


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