National Veterinary Services Laboratories

Equine Infectious Anemia Virus Antibody

Proficiency Test Summary

1. Composition of proficiency test panel: The equine infectious anemia (EIA) virus antibody 

panel consists of twenty, 0.6 ml samples of equine serum. The panel contains negative, weak 

positive and strong positive samples, and includes blind duplicates. The samples are labeled 

with the test acronym and calendar year (e.g., EIA 2013), a panel set number (e.g., Set 254), and 

a sample number (Sample 1 through 20). The samples are scrambled between sets. 

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 or below -20° C in a non-frost free freezer.

4. Sample preparation/selection criteria: Samples with high, medium, and low concentrations 

of EIA antibody are chosen for incorporation into the panel. Antibody levels arise from naturally 

acquired infections. Each panel member is tested at least seven (7) times. At least three NVSL 

technicians perform the testing and all licensed test kits are utilized in the sample selection 

testing. Note: NVSL is an OIE reference laboratory for EIA.

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

testing of the panel has determined that normal shipping and handling conditions do not change 

the panel. Panel sets of each lot of proficiency panels are used to confirm stability after final 

preparation. 

6. Timing of the proficiency test distribution and data collection: The EIA proficiency test 

is administered annually, customarily in the month of May. 

7. Test method: Performance and interpretation of the EIA proficiency must be conducted 

using licensed kit manufacturer’s directions or as described in NVSL SOP-EO-0034. 

The EIA AGID and ELISA tests at NVSL are ISO17025 accredited. 

8. Submitting test results: Participating laboratories are required to have data submitted for 

scoring no more than four (4) weeks after panel distribution. Results are reported to the NVSL 

by fax, mail, or email. One set of results is reported from each laboratory, along with test kit

information. 

9. Scoring of individual panel samples: The EIA proficiency test is an annual test of approved 

EIA laboratories. Procedures for approved laboratories are found in 9CFR part 75.4 and in VS 

Memorandum 555.16. One result for each sample is reported per laboratory. Sample results are 

reported as positive or negative. 

Revision: April 2013
10. Laboratory pass/fail criteria: The final score is based on the identification of positive and 

negative samples. An NVSL/CVB statistician is consulted to determine the appropriate pass/fail 

cutoff. 

11. Reporting laboratory test scores: Results for each laboratory are reported to the individual 

laboratory director and to the appropriate AVIC for the laboratory’s location. Reports include 

individual laboratory results for each sample as well as summary results of participants in the 

proficiency test. Results are compiled and reported within 30-60 days of the due date for receipt 

of participants’ results.

12. Remedial actions required for failing laboratories: Laboratories that do not pass on the 

first attempt are given the option of purchasing a second panel for a retest. Laboratories that fail 

the proficiency test are encouraged to contact subject matter experts at NVSL for discussion of 

methods and resolution of potential areas of concern. If a failing laboratory declines to take, or 

does not pass, the retest the laboratory is recommended for removal from the list of approved 

laboratories for EIA testing according to 9CFR Part 75.4. Laboratories that are removed from 

the approved list are advised that retraining through the NVSL EIA training course is needed for 

reconsideration of approval. All appeals are documented and evaluated on a case-by-case basis. 

13. Special requirements: Restrictions - The EIA proficiency test is only provided in the 

United States to laboratories that are currently approved for EIA testing. As of 2013, there are 

approximately 460 approved EIA laboratories in the United States. 

The current list of approved laboratories can be found at: 

http://www.aphis.usda.gov/animal_health/lab_info_services/approved_labs.shtml

Licensed EIA testing reagents may only be purchased by approved laboratories. International 

requests for the EIA proficiency panel are considered on a case-by-case basis and must follow 

applicable authorization and permit requirements. 

Revision: April 2013