Porcine Lymphotropic Herpesviruses Triplex (PLHV-1, PLHV-2, PLHV-3) Real-Time PCR

Service type
Molecular Diagnostics/PCR
Non-human Primate
Days tested
Tuesdays. In most cases, samples need to be in the lab by noon the day before the scheduled test for processing and preparation.
Turnaround time
7 business days. In order to perform necessary processing and preparation, samples in most cases should be received in the lab by noon the day before the scheduled testing day.
Specimen Requirements

1) EDTA whole blood, 2) EDTA blood for buffy coat (prepared in the lab), 3) spleen, 4) tissue homogenate (including lymphoid tissue) 

Shipping container
1,2) 3-5mL purple top (EDTA) blood tube 3,4) Whirl-Pak plastic bag or cryovial(s)
Frozen Gel Packs
Location Term
St. Paul (VDL)
Submission Form(s)

Following the guidelines listed under the Submitted Specimen Requirements will provide an adequate sample volume to conduct this test. If multiple tests are to be requested on a specimen, there may not be adequate sample volume to perform each test. Please submit an adequate sample volume to meet the requirements of each test.

Test update

We have been testing for porcine lymphotropic herpesviruses (PLHV; also referred to as porcine gammaherpesviruses) here at UMN VDL using a conventional gel-based assay, which provides a positive or negative result but does not differentiate between PLHV-1, PLHV-2, or PLHV-3. 

We've recently developed a new PLHV multiplex real-time PCR assay and will start running this new assay this week as our routine PLHV test. The gel-based assay will still be available by special request for a period of time but will eventually be retired. If you need the gel-based assay for specific research projects or for any other reason, please contact me and let me know the details. Also, when submitting for the gel-based test please specify/write-in "PLHV gel-based PCR" on your submission forms. The latest version of the Swine Health Test Chart is on our website (Link to current form) There is a checkbox to request the real-time PLHV PCR. 

Improvements incorporated into this new assay include the utilization of real-time reagents so that non-negative results will now include a Cycle Threshold (Ct) value, use of differential primers and probes so that PLHV-1, PLHV-2, and PLHV-3 are being reported separately, and the addition of an internal control reaction to ensure that the PCR reaction within each well is functioning as expected. 

For our accreditation purposes, the PLHV-2 component of this triplex assay is considered to be in the research/validation phase because we haven't been able to find/acquire PLHV-2 positive field samples. Based on in-silico testing with the primers and probes against sequences in GenBank and actual testing using a synthetic plasmid created based on GenBank sequences, this assay is capable of detecting PLHV-2. Once we reach the minimum number of PLHV-2 positive samples and confirm them with Sanger sequencing, there will no longer be a disclaimer applied to that portion of the test. 

Based on comparisons of detection for 154 samples tested with the new real-time assay as compared to the same samples on the gel-based assay (previous gold standard for us), the sensitivity was 100% (90/90 gel-based PCR positives tested positive on the real-time test) and specificity was 98.46% (out of the 64 gel-based PCR negative samples, one tested positive on the real-time test with a Ct 33 for PLHV-1; this was confirmed by repeat testng and gB Sanger sequencing). The consistent limit of detection for all three types based on triplicate dilutions tested on three different testing days was 93 copies per reaction, with frequent detection in the Suspect range (Ct >=36 but <40) down to 10 copies per reaction.

Please contact us if you have questions. 

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