West Nile Virus (PRNT) [Referral]

Detection of antibodies to West Nile virus using the plaque reduction neutralization test (PRNT). This test is used to assess vaccine titers in horses or to test non-equine species for antibodies to West Nile virus.

2 mL serum

Collect serum from clotted blood in a non-additive tube (e.g. plain red top or serum separator). When possible, transfer clear serum off the clot into a new tube. Excessively hemolyzed samples are not acceptable for this test.

Glass or plastic tube with no anticoagulant additives.

Label all samples with unique identifiers. 

For multiple samples, number tubes consecutively using a permanent marker or adhesive label. Include a list of sample names/numbers or the Excel specimen import spreadsheet with submittal form. Place the tubes in consecutive, numerical order in cardboard boxes designated for tubes. Do not submit loose in bags. 

Use cold packs during hot weather, especially if shipping serum samples on the clot. Overnight shipping is recommended.

This test is performed at the USDA National Veterinary Services Laboratory in Ames, IA. Prices listed for tests performed outside TVMDL may not include referral lab accession fees and are subject to change without notice. A processing and forwarding fee is added to all referral tests. Turnaround times vary depending on shipping time and the referral lab’s schedule. Please include a clinical history and county of origin for all equine encephalitis serology requests. This test is most appropriate for assessing vaccine titers in equines; please request the IgM ELISA for clinically-ill animals.