Laboratory testing: What could possibly go wrong?

There are non-pathologic variables or errors that affect laboratory results that may lead to the misdiagnosis and mistreatment of veterinary patients. These non-pathologic variables can be divided into pre-analytical, analytical, and post-analytical. Analytical and post-analytic variables are the responsibility of the laboratory, as they involve the actual laboratory testing and reporting of results, respectively. Pre-analytical variables occur from patient identification and preparation up until the specimen is evaluated in the laboratory. These errors are therefore, the responsibility of the person collecting and submitting the samples and of the laboratory.

Pre-analytical variables can be divided into those that are preventable, and those that are unavoidable because they are inherent to the specimen (e.g. ictericia). Preventable pre-analytical errors include problems with specimen collection (e.g. additive cross-contamination, wrong tube used, insufficient specimen volume) and specimen handling (e.g. delayed separation of serum/plasma from cells, or delayed submission of the specimen). This summary will focus in some of the preventable pre-analytical variables that affect clinical pathology specimens submitted for complete blood cell counts (CBCs) and chemistry panel. For more information on this topic you can refer to the American Society for Veterinary Clinical Pathology (ASVCP) quality assurance guidelines available online at