title: Variability in results of the microscopic agglutination test in dogs with clinical leptospirosis and dogs vaccinated against leptospirosis.
abstract: BACKGROUND
  The microscopic agglutination test (MAT) is commonly used for the diagnosis of canine leptospirosis. In dogs it is sometimes suggested that the serogroup with the highest MAT titer is the infecting serogroup; however, this is not true in humans with confirmed leptospirosis. We sought to investigate the value of MAT results in predicting the infecting serogroup by comparing results across several laboratories and within individual dogs over time.
  
  
  OBJECTIVE
  To examine the variability in MAT results across different laboratories in dogs recently vaccinated against leptospirosis, and in dogs with clinical leptospirosis, and to investigate variability over time in MAT results in individual dogs with leptospirosis.
  
  
  METHODS
  Eighteen dogs from a research colony, 9 of which had been vaccinated against leptospirosis, and 17 dogs clinically diagnosed with leptospirosis.
  
  
  METHODS
  Serum samples were submitted to up to 5 veterinary diagnostic laboratories for MAT titers from each dog on at least 1 occasion. MAT results also were followed over time in 6 dogs diagnosed with leptospirosis.
  
  
  RESULTS
  MAT results were discordant across different laboratories in dogs recently vaccinated against leptospirosis and in dogs with clinical leptospirosis. MAT results varied over time in individual dogs with the disease.
  
  
  CONCLUSIONS
  The MAT is a valuable test for the diagnosis of leptospirosis in dogs, but it is unlikely that test results can be used to predict the infecting serogroup. Laboratories offering the MAT should consider participation in a proficiency scheme.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1678, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Miller
authors.forename: K M
authors.initials: KM
authors.lastname: Annis
authors.forename: M R
authors.initials: MR
authors.lastname: Lappin
authors.forename: K F
authors.initials: KF
authors.lastname: Lunn
mesh_terms: D000372:Agglutination Tests / Q000379:methods / Q000592:standards / Q000662:veterinary*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D004283:Dog Diseases / Q000097:blood / Q000175:diagnosis* / Q000517:prevention & control; D004285:Dogs; D007919:Leptospira / Q000276:immunology*; D007922:Leptospirosis / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control / Q000662:veterinary*; D015203:Reproducibility of Results; D013047:Specific Pathogen-Free Organisms
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines