title: Diagnostic value of two commercial chromatographic "patient-side" tests in the diagnosis of acute canine leptospirosis.
abstract: OBJECTIVE
  To determine the diagnostic performance of two patient-side tests (RDT-1: Test-it™ and RDT-2 Witness®Lepto) in the early diagnosis of canine leptospirosis.
  
  
  METHODS
  Retrospective study of 108 dogs with leptospirosis and 53 controls. Leptospirosis was diagnosed based on compatible clinical and clinicopathologic signs and either a single microscopic agglutination test titre_ >800 (n=49), seroconversion (n=53), positive urine real time PCR (RT-PCR) (n=1), evidence of spirochaetes in silver-stained tissues (n=1) or a combination of these (n=4). Leptospirosis was excluded in dogs with a convincing alternative diagnosis and single microscopic agglutination testing titres _<200 (n=46) or lack of seroconversion (n=7). Indices of diagnostic accuracy of the rapid diagnostic tests were calculated by comparing admission rapid diagnostic test results to the final disease status.
  
  
  RESULTS
  Rapid diagnostic test-1 was performed in 118 dogs, rapid diagnostic test-2 in 69 dogs and both tests in 26 dogs. Weak positive results occurred frequently representing 22·6% (rapid diagnostic test-1) and 32·3% (rapid diagnostic test-2) of all positive tests in dogs with leptospirosis. If weak positive rapid diagnostic tests were considered positive, rapid diagnostic test-1 and rapid diagnostic test-2 had sensitivities of 82 and 76%, specificities of 91 and 100%, positive predictive values of 94% and 100% and negative predictive values of 73% and 74%, respectively. There were some technical problems with rapid diagnostic test-1.
  
  
  CONCLUSIONS
  The diagnostic performance of the rapid diagnostic tests is similar to that reported for the microscopic agglutination test. Both can support a diagnosis of leptospirosis with high specificity but leptospirosis cannot be excluded based on a negative admission test result. Both RDTs are useful in conjunction with other confirmatory tests.
authors.affiliation: Division of Small Animal Internal Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
authors.forename: C I
authors.initials: CI
authors.lastname: Gloor
authors.affiliation: Division of Small Animal Internal Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Schweighauser
authors.affiliation: Division of Small Animal Internal Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
authors.forename: T
authors.identifier: http://orcid.org/0000-0002-6693-5365
authors.initials: T
authors.lastname: Francey
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University Bern, Bern 3012, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Rodriguez-Campos
authors.affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, University Bern, Bern 3097, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Vidondo
authors.affiliation: 3007, Bern, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Bigler
authors.affiliation: Division of Small Animal Internal Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Schuller
mesh_terms: D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D002846:Chromatography, Affinity / Q000662:veterinary; D004283:Dog Diseases / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology; D004285:Dogs; D042241:Early Diagnosis; D007919:Leptospira / Q000276:immunology / Q000302:isolation & purification; D007922:Leptospirosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D011933:Reagent Kits, Diagnostic; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012189:Retrospective Studies; D000069078:Seroconversion
chemical_list: D011933:Reagent Kits, Diagnostic