National Veterinary Services Laboratories (NVSL) 

Leptospira microscopic agglutination test (MAT) 

Proficiency Test Summary 

1. Composition of proficiency test panel: The panel consists of 20 serum samples to be

evaluated against five Leptospira antigens. Individual samples consist of 0.50 ml of serum 

provided in bottles with rubber stoppers and aluminum seals. Up to four results are accepted 

from individual participants at a laboratory. 

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

3. Storage conditions: Short term (up to 28 days), store at 4° ± 2° C. Long term, store at

<-20° C in a non-frost free freezer. 

4. Sample preparation/selection criteria: Samples consist of extensively evaluated sera that

have been studied for reproducibility. The panel is assembled by the Bacterial Identification 

Section of the Diagnostic Bacteriology Laboratory (DBL), NVSL, prior to shipment to 

participating laboratories to ensure that the samples have measurable results. 

5. Panel quality control: Samples are monitored for reproducibility. Bulk volumes of serum are

filtered using a 0.45 μm filter prior to bottling. 

6. Timing of the proficiency test distribution: The Leptospira MAT is available once every

three years. 

7. Test method: Performance of the Leptospira MAT should be conducted by following the

protocol published in the Proceedings of the 1987 United States Animal Health Association. The 

protocol is available from the NVSL upon request. 

8. Submitting test results: Participants are required to submit data for scoring within 30 days of

panel distribution. Results are reported to the laboratory director for all participants. 

9. Scoring of individual panel samples: The results of each proficiency test participant are

evaluated based on identity, accuracy, and total composite score. For the purpose of identity 

scoring, the median titer value for a sample is determined from the titers provided by all 

participants. Each time the participant titer matches the median for a sample (in terms of 

positive = positive or negative = negative) five points are awarded. If a sample is misidentified, 

0 points are given. A misidentified sample is one where the median titer for the sample was 

positive at a titer of 100 or greater, and the participant identified it as negative, or vice versa. In 

terms of scoring the check test for accuracy, the median titer is determined for each sample and 

antigen using the responses of all check test participants. If the titer reported by a participant 

matches that of the median titer, five points are awarded. For each two-fold dilution deviation 

from the median titer, one point is deducted. A total combined score is determined using identity 

and accuracy scores. 

October 21, 2013
10. Laboratory pass/fail criteria: The results from this proficiency test are not used to pass or 

fail laboratories, but rather to assist them in improving Leptospira MAT performance. 

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

laboratory director. Final results are compiled and reported within 60-90 days of the deadline for 

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

laboratory, and summary results from all laboratories are provided with participants listed in an 

anonymous coded format as part of the final report. Participant and laboratory identity are 

conserved. 

12. Remedial actions required for failing laboratories: The results from this proficiency test 

are not used to pass or fail laboratories, but rather to assist them in improving Leptospira MAT 

performance. 

13. Special requirements: