Diagnostic Labs, Breakpoints and Antimicrobial Resistance

Background
Veterinarians depend on laboratory medicine is every day. A clinician’s medical decision are based on the use of results of different laboratory tests; therefore, diagnostic testing is an integral part of clinical medicine. Diverse factors can be associated with the inadequate use of the clinical diagnostic laboratory (CDL) in veterinary medicine. While some of these factors are strictly related to situations that are not controlled by the clinician, such as cost of testing, a limited testing availability, and lack of harmonization among the different methods used, the other factors are influenced by the clinician, such as their lack of knowledge when selecting the best diagnostic test, poor sample collection, and inappropriate interpretation of the results.

The process of laboratory testing comprises three phases, pre-analytical, analytical and post-analytical [1, 2]. These phases are crucial for performing diagnostic testing and must be considered by clinical microbiology laboratories (CML) the veterinarian when requesting a test. The optimal use of CDLs is based on the close relationship between the clinician and the diagnostic laboratory. Although molecular diagnostics play a very important role in the specialty of clinical diagnostics in the new era, “culture and susceptibility” remains as one of the most common requests received by the CMLs. Since antimicrobials were discovered, different antimicrobial susceptibility methods have been employed. CMLs implement the most convenient method according to the number of requested tests, sample origin (animal species) and cost of testing. To ensure that the selected method(s) is properly employed and the results are accurate, CMLs should implement a quality assurance program [3, 4]. Therefore, when performing antimicrobial susceptibility testing, CMLs, researchers and the pharmaceutical industry must adhere to the guidance and standards of the Clinical and Laboratory Standard Institute (CLSI). [...]