ISSUE No. 35 June 2007 LAB NEWS AND VIEWS
emerging PRRSV variants. In July of 2007, we will
launch a second generation PRRSV test that utilizes
new NA PRRSV primers and probe designed by Steven
Kleiboeker DVM, PhD, University of Missouri, based on
current sequencing information. These new primers and
probe target highly conserved regions in the 3’-
untranslated region (UTR) of the NA PRRS virus.
Before initiating the process to replace the current test,
research efforts confirmed that the new NA primers and
probe could be successfully multiplexed with the current
EU primers and probe without sacrificing sensitivity and
specificity. So, the simultaneous detection and
discrimination of the NA and EU strains and their
detection limits remain unchanged.
Validation of the new real-time 3’-UTR NA/EU multiplex
PRRSV PCR test was performed in parallel with our
BI PRRSV Testing Proficiency Panels current PRRSV PCR test on 116 field samples. The
The PRRSV proficiency panel was established by data was compared to assure that the performance of
Boehringer Ingelheim (BI) and is provided free of charge the new test was equivalent or superior to the current
to interested laboratories. It is an unbiased way to test offered by Gallant. The validation data
assess the testing abilities of laboratories conducting demonstrated that the new 3’-UTR PRRSV real-time
PCR tests to detect PRRS virus. BI submits blinded PCR test had excellent correlation (97.4%) with
samples of virus (diluted to produce both positives and Gallant’s original PRRSV real-time PCR test.
negatives) to participating laboratories. The results are In addition, analysis of PRRSV data collected over a
reported to BI who analyze the data and provide an one year period identified 5% of the farms/systems
anonymous comparative data table to participants. tested at Gallant had PRRSV variants that were
Gallant Labs participated in the September 2006 and detected more efficiently with the new 3’-UTR NA/EU
March 2007 BI proficiency panels with excellent results. multiplex PRRSV real-time PCR test. This suggests
Comparison of the PRRSV proficiency data positions that the new 3’-UTR directed primers and probe would
Gallant among the labs exhibiting high sensitivity without offer increased sensitivity, detection and quantification
producing false positives. In addition, Gallant’s virus of emerging NA PRRSV variants in the clinical samples
quantitation results are in agreement with other real-time analyzed.
PCR testing labs that reported virus titers.
Benefits of the new PRRSV multiplex assay to
Next Generation Real Time RT-PCR Test for Clients:
PRRSV Launch By Gallant Custom Laboratories
Improved detection of all NA PRRSV strains
One of the challenges for both control and testing of
including emerging NA PRRSV variants.
PRRS is the continual genetic mutation of the PRRS
virus. To address this concern, Gallant continues to More accurate estimation of NA PRRS virus titer.
make molecular improvements to our North American Detection limit is unchanged and remains at 5 virus
(NA) and European (EU) multiplex PRRSV real-time copies or better.
PCR test to ensure that the test we provide is sensitive Both NA and EU PRRS viruses can be simultaneous
and minimizes the possibility of false negatives due to detected, identified and quantified in one test.
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