National Veterinary Services Laboratories 

Equine Piroplasmosis - Babesia caballi and Theileria (Babesia) equi

Proficiency Test Summary - cELISA 

1. Composition of proficiency test panels: The equine piroplasmosis test panel consists of 15

vials of characterized equine serum for both species. Individual samples consist of 0.5 ml of

serum provided in bottles with rubber stoppers and aluminum seals.

2. Cost of proficiency test: Click here to view the 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: Store at 4° ± 2° C for short term storage (up to 30 days).

4. Sample preparation/selection criteria: Serum samples are selected to create panels with an

expected test result range from negative to strong positive. No more than two samples in

each category are used in duplicate in the panel. Sample panels consist of well characterized

control sera that have been evaluated extensively over time by the VMRD cELISA for equine

piroplasmosis. The panels are retested by the Serology Section of the Diagnostic

Bacteriology Laboratory (DBL), NVSL, prior to shipment to participating laboratories to

ensure that the samples are giving expected results.

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

volumes of serum are filtered using a 0.45 μm filter and tested prior to bottling. Samples

with results that vary widely between participating laboratories are considered to be outliers,

and are not used in determining the pass/fail criteria.

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

Serology Proficiency Test is administered once a year. The month targeted for distribution is

October for annual renewals. Individuals may order the test throughout the year if additional

testers are required by the laboratory prior to the annual test.

7. Test method: Performance and interpretation of the Equine Piroplasmosis Serology

Proficiency Test should be conducted according to the manufacturer’s kit inserts for the

commercial cELISAs currently available in the United States (Babesia caballi and Babesia

equi Antibody Test Kits, cELISA, VMRD Inc., Pullman, WA).

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

more than 30 days after test panel distribution. Results are reported to the Piroplasmosis

Proficiency Test Coordinator by fax, e-mail or mail. Both qualitative (positive/negative) and

quantitative (percent inhibition) results must be reported for each sample and for the serum

controls.

9. Scoring of individual panel samples: For each sample, a result is considered to be

correct based on correctly identifying the sample as positive or negative. The percent

inhibition values are not used as criteria for scoring the proficiency test.

10. Laboratory pass/fail criteria: A participant must correctly identify all positive sera, and

may miss up to 2 negative sera in order to pass the proficiency test. A laboratory is required

October 21, 2013
to have at least one participant that passes the proficiency test in order to be approved to 

order and to perform the commercial cELISA kits for equine piroplasmosis. Individual 

participants in an approved laboratory are required to pass the proficiency test before 

performing the test on an official basis. 

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

Piroplasmosis Proficiency Test contact. Final results are compiled and reported within 30 

days of receipt of participants’ results. Results of individual laboratories are reported only to 

that laboratory. 

12. Remedial actions required for failing laboratories: Laboratories that do not have any 

individual participants passing the proficiency test on their first attempt may purchase 

additional test panels and retake the test. Additional individuals may be added to the list of 

approved participants at any time by successfully passing the proficiency test.

13. Special requirements: The Piroplasmosis Serology Proficiency Test is intended to provide 

the NVSL with evidence of the proficiency of laboratories and individuals to test equids by 

the commercial cELISAs for equine piroplasmosis. This approval is required to purchase and 

to perform the cELISA for the purposes of export and for intra- and interstate movement of 

equids. Testing for other purposes, such as import and Foreign Animal Disease 

investigations, is reserved for the NVSL.