National Veterinary Services Laboratories

Brucella abortus Serology

Proficiency Test Summary

1. Composition of proficiency test panel: The panel consists of 20 samples of bovine 

serum. Each panel may be used for up to 9 different brucellosis serology tests (see 

section 7 below). Sample kits are provided in 3 different volumes (0.25 ml, 1.0 ml, or 

1.25 ml), as required to perform the number of tests each participant is assigned to 

perform.

2. Cost of proficiency test: There is no charge for proficiency testing as part of the 

Cooperative State-Federal Brucellosis Eradication Program. Refer to current reagent 

catalog for pricing for other uses. 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: Serum samples are selected to create a panel 

with three expected result categories: strong positive, intermediate, and negative. No 

more than two samples in each category are used in duplicate in the panel. Samples are 

assigned to each category according to prior test results. Samples are tested at least 2-3 

times over a period greater than one year, and the entire panel is tested by the Serology 

Section of the Diagnostic Bacteriology Laboratory - after sterile filtering and prior to 

bottling for shipment to participating laboratories.

5. Panel quality control: Samples are monitored for sterility, stability, and 

reproducibility. Sera are filtered and tested for sterility prior to bottling. Samples with 

results that vary widely between participating laboratories (less than 66% agreement after 

acceptable standard deviations are determined) 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 Brucellosis 

Serology Proficiency Test is administered once a year, generally in May, for U.S. 

approved labs. 

7. Test method: Performance and interpretation of the Brucellosis Serology Proficiency 

Test should be conducted using the current version of the NVSL test protocol or the 

manufacturer’s kit insert for each test that the participant wishes to be certified in: 

Standard Plate Test - SPT (SEROPRO1023), BAPA (SEROPRO1024), Standard Tube 

Test - STT (SEROPRO1026), CFT (SEROPRO1022), Rivanol (SEROPRO1025), Card 

Test (SEROPRO1027), RAP (SEROPRO1028), PCFIA (kit insert), FPA (microplate -

SEROPRO1050, tube - SEROPRO1051).

8. Submitting test results: Participants are required to have data submitted for scoring 

no more than 4 weeks after panel distribution. Results are reported to the Brucellosis 

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Proficiency Test Coordinator by fax, email, or mail. Reporting results via email using 

electronic score sheets provided is preferred in order to increase efficiency and decrease 

transcription errors.

Test results are reported as follows:

BAPA and Card: 0 (Negative), 1 (Positive).

Rivanol, SPT and STT: 0 (Negative), 1 to 8 (Incomplete @ 1:25 to Positive @ 1:200).

RAP: Numerical values to determine mean scores, then converted to Positive/Negative

PCFIA: Numerical values.

FPA : Negative/Positive

CFT: 0 (Negative), 1-28 (1+ 1:10 to 4+ 1:640).

9. Scoring of individual panel samples: For each sample tested by a qualitative test 

(BAPA, Card), a result is considered as passing if a known negative sample is identified 

as negative and if a known positive sample is identified as positive. For each sample 

tested by a quantitative test (Rivanol, SPT, STT, RAP, PCFIA, FPA, CFT), a result is 

considered as passing based on a statistical analysis of the dispersion of the result from 

the mean of the results from all participants (e.g., within one standard deviation from the 

mean).

10. Laboratory pass/fail criteria: A final score of ≥90% correct results for each test is 

considered passing. Individual participants from a laboratory must pass the proficiency 

test for each test in order for that person to perform that particular test (e.g., Card, STT, 

etc.). Laboratories are considered to be certified for a particular test if at least one 

individual from that laboratory has passed the current proficiency test.

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

the individual laboratory director or Brucella proficiency test contact, the AVIC, and 

appropriate APHIS Brucella Program staff. Final results are compiled and reported

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

12. Remedial actions required for failing laboratories: Individual personnel from a 

laboratory that do not pass on the first attempt are offered a retest. Failure to pass on the 

retest may mean that participant is not allowed to administer the failed procedure. If all 

personnel form a laboratory fail, the laboratory is not certified to perform that particular 

test. Those laboratories that show repeated failed attempts are encouraged to contact the 

Brucella and Mycobacteria Reagents Team (BMRT) Leader for discussion of remedial 

actions. These laboratories are asked to test again in the next round of testing. If 

requested by the laboratory, additional training panels may be provided to the laboratory 

for practice purposes.

13. Special requirements: The Brucella abortus Serology Proficiency Test is intended 

to certify individual technicians in approved laboratories to perform official testing as 

part of the Cooperative State-Federal Brucellosis Eradication Program.

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