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  Home > Services and Fees > Viral PCR > Guidelines for BVD PCR Ear Notch Screening
 

Guidelines for BVD PCR Ear Notch Screening

General Information

Submitted ear notches for BVD screening will be processed and then pooled in groups of up to 50 samples for PCR testing. Large numbers of samples will be divided into groups of 50 (or smaller if a remainder exists). If a pool tests positive, individual samples will be tested by antigen capture ELISA to identify potential persistently infected animals.

Submission Guidelines

Fresh ear notch skin should be submitted frozen and run within 30 days of collection.

  • Submit a fresh sample of ear tissue approximately 1 cm x 1 cm (use 1/2 inch notching pliers).
  • Place ear notch in an empty plain 6 or 10 ml red-top tube (no additive or gel).
  • Samples not submitted as such are subject to an additional processing fee per tube in addition to the probability of delay in testing and reporting.
  • Tubes should be sent chilled on ice packs, observing proper shipment procedures.
  • Samples can be stored frozen but the pooled PCR test should be run within 30 days of sample collection.
  • Disinfect ear notching instruments and other equipment between samples, making sure to thoroughly rinse the disinfectant before collecting the next sample.

Pooling samples in groups of 50 or less substantially reduces the per-animal diagnostic cost compared to currently available individual tests, yet maintains a reasonable number of samples to test individually in the event a pool is positive.

It is necessary to understand that pooled diagnostic procedures such as this should be considered screening tests only. Pooling procedures can result in decreased sensitivity over individual tests. In cases in which individual animals are represented as BVD PI-test negative (e.g. purebred animals for sale), individual diagnostics utilizing the fresh ear notch antigen capture ELISA, formalin-fixed ear notch IHC, or serum PCR should be performed.

PCR procedures, due to their enhanced sensitivity, may detect transiently infected animals more often than other tests such as the ear-notch antigen capture ELISA. Therefore, it is possible to experience scenarios in which a pool is PCR-positive but the individual samples are negative on the follow-up individual ear-notch tests (as per Drs. Chris Chase and Jane Christopher-Hennings, South Dakota State University, Brookings, SD).

If you have any questions about the procedure, or proper submission of samples, please contact us.


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