Test Basics

The ability of an instrument to perform a test does not guarantee that the generated results are accurate. Ensuring that laboratory equipment is providing reliable data requires a comprehensive plan that encompasses both common sense practices aimed at preventing errors at each stage of the testing process and standard operating procedures (SOPs) to validate and […]

Changes in laboratory results can be physiologic (i.e. expected due to age, breed, sex, physiologic status such as pregnancy, lactation) or associated with disease. Thus, interpretation of results need to take into account expected physiologic changes in order to determine what is expected due to the animal and what is indicative or supports underlying disease. Prematurity

Generally, at Cornell University, we interpret results in several ways: Detection of abnormal results: This is usually accomplished by observing test results outside reference intervals. If reference intervals are not established for the species, we generally go to the literature to provide guidelines as to how to interpret changes. Some abnormal results are not diagnostically

Close attention must be paid to all aspects of sample collection, handling and storage, to ensure the most accurate clinical pathologic results. This section provides general guidelines and recommendations for optimally collecting and submitting blood samples for clinical pathologic testing. More detailed information on specific recommendations for individual tests can be found under related sections

Common interferences (hemolysis from rupturing of RBCs, icterus, lipemia) and blood sample collection (e.g. too little blood into too much EDTA), handling and storage problems can affect the results of hematologic and clinical chemistry testing. A brief summary of common changes that we see is given below. The most common interferent is hemolysis (Whipple et

Interferences are substances such as lipids, free hemoglobin and bilirubin (also globulins and drugs) which affect the results of clinical pathologic tests, as they are being performed. They are considered analytical variables because they directly interfere with test performance (and results) in various ways, but also are pre analytical variables, because some (lipids, free hemoglobin,

Laboratory data is usually interpreted with respect to population-based reference intervals but for some analytes in which intraindividual (within animal) variation is less than interindividual (between animal) variation, subject-based reference values may be more applicable (see more below). Population-based reference intervals Reference intervals (also called, although incorrectly, normal ranges or reference ranges) are intervals calculated

Many factors other than disease influence the results of chemistry tests. These factors may be preanalytical, analytical and post-analytical. Extra-analytic errors is applied to errors in which the cause is not identified or due to more than one factor (Whipple et al 2020). Preanalytical variables are variables associated with the patient, sample collection and sample handling.

In this section of the site, we provide information on the following: Sample collection: General information on how sample collection, handling and storage can affect results of clinical pathologic testing. Specific details on sample collection for hematologic, hemostasis, urinalysis, chemistry and cytologic test results are given in each related section. Test interpretation: General principles of interpreting