National Veterinary Services Laboratories 

Pseudorabies –gI Enzyme-Linked Immunosorbent Assay (PRV-gI ELISA) 

Proficiency Test Summary 

1. Composition of proficiency test panel: The panel consists of twenty, 500 μl samples of 

sera. The panel contains positive and negative sera. The samples are labeled with numbers 1-20.

2. Cost of proficiency test: Click here to view current NVSL Catalog of Reagents. Additional 

information on diagnostic reagents, including ordering, payments, shipping details and fees, is 

located at www.aphis.usda.gov/nvsl. Then click on the Reagents and Proficiency Tests link.

3. Storage conditions: Short term (up to 7 days) store at 4° ± 2° C. Long term (over 7 days) 

store at <-20° C in a non-frost free freezer.

4. Sample preparation/selection criteria: Samples with positive and negative results are 

chosen for incorporation into the panel. Antibody levels arise from naturally and experimentally 

acquired infections. Each panel sample is tested at least five (5) times by a minimum of two 

technicians in the Diagnostic Virology Laboratory (DVL), at NVSL.

5. Panel quality control: Samples are monitored for stability and reproducibility. Sera are 

filtered prior to bottling.

6. Timing of the proficiency test distribution and data collection: The PRV-gI ELISA panel 

is administered once a year generally in January for United States approved laboratories. The 

panel is administered internationally upon request.

7. Test method: Performance and interpretation of the Pseudorabies –gI Enzyme-Linked 

Immunosorbent Assay for sera is per the manufacturer’s instructions.

8. Submitting test results: Participants are required to have data submitted for scoring no more 

than three (3) weeks after panel distribution. Results are reported to the Head of the 

Bovine/Porcine/Aquaculture Section at the DVL, NVSL, or designee by fax, e-mail, or mail. 

9. Scoring of individual panel samples: For each sample, a participant is considered as 

passing if the known negative sample is identified as negative. A participant is considered as 

passing if the known positive sample is identified as positive.

10. Personnel pass/fail criteria: The final score is based on the identification of positive and 

negative samples. Statistical analysis to determine pass/fail level is done by comparing results 

when at least 90% of participants taking the panel have submitted results.

11. Reporting laboratory test scores (U.S. laboratories only): Results for each person are 

reported to the individual laboratory director and the AVIC. Pass letters are sent to laboratory 

directors within 60-90 days of the deadline for receipt of participants’ results. A copy of the 

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results for all National Animal Health Laboratory Network (NAHLN) laboratories is sent to the 

NAHLN Program Office. 

12. Remedial actions required for failing laboratory personnel (U.S. laboratories only):

Personnel are given a second chance to pass a proficiency panel. If they fail a second time, PRV 

testing by that participant is stopped, personnel must undergo training (defined by NVSL), and 

the person must pass a panel before tasting can begin again.

13. Special requirements (U.S. laboratories only): Laboratories must meet requirements 

stated in the Code of Federal Regulations (CFR) title 9, part 85. Participating NAHLN 

laboratories must comply with provisions outlined in the NAHLN Laboratory Qualification 

Checklist for Membership of a Veterinary Diagnostic Laboratory. Training received at a 

laboratory other than the NVSL must be approved by the NAHLN Program Office in 

conjunction with NVSL.

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