Content continues after advertisement

Point-of-Care Testing for Leptospirosis

George E. Moore, DVM, PhD, DACVIM (Small Animal), DACVPM (Epi), Purdue University

Infectious Disease

|July 2019

Sign in to Print/View PDF

In the Literature

Troìa R, Balboni A, Zamagni S, et al. Prospective evaluation of rapid point-of-care tests for the diagnosis of acute leptospirosis in dogs. Vet J. 2018;237:37-42.


FROM THE PAGE …

Leptospirosis is an important disease differential in dogs with systemic illness, but testing for this potentially fatal, zoonotic disease is difficult, as no test is consistently 100% sensitive (ie, no false-negative results) or 100% specific (ie, no false-positive results).

Diagnostic laboratories offer quantitative tests for leptospiral antibodies (serovar titers by microscopic agglutination testing [MAT]) and antigens (conventional PCR or real-time quantitative PCR [qPCR] tests of blood and urine) for disease diagnosis. More recently, rapid, in-house, point-of-care immunodiagnostic tests for detection of immunoglobulin M and/or immunoglobulin G have become available to clinicians.1,2

This study evaluated and compared 2 in-house tests for diagnosis of acute leptospirosis in dogs. Dogs with suspected acute leptospirosis (n = 89) were tested, and results were compared with a clinical diagnosis based on MAT and/or qPCR. Classification of 42 dogs with confirmed leptospirosis was based on a single high MAT titer on admission (n = 32), a 4-fold increase in convalescent MAT (n = 4) results, and/or a positive blood (n = 5) and/or urine qPCR (n = 5) result. These results suggest differing duration of infection in these clinical cases.

Evaluation of the point-of-care antibody tests compared with this classification indicated both tests to be comparable with and possibly more sensitive than MAT. Comparison of calculated sensitivity, specificity, and accuracy is difficult due to the variety of clinical cases, duration of illness, and criteria used to classify cases as confirmed. Nevertheless, in-house tests that detect immunoglobulin M may signal increased titers a few days earlier than immunoglobulin G-based tests.3


… TO YOUR PATIENTS

Key pearls to put into practice:

1

Sensitivity and specificity of different leptospirosis tests in dogs vary by time since infection, so the time since onset of clinical signs should be considered when selecting tests.

2

Due to <100% sensitivity for all available tests, a negative test result does not rule out disease in acute illness.

 

3

Because interpretation of in-house serologic tests in properly vaccinated (4-serovar) dogs is difficult, PCR testing is recommended if vaccine failure is suspected.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© 2023 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | DMCA Copyright | Privacy Policy | Acceptable Use Policy