Clinicopathologic Testing
The results of clinicopathologic tests often shorten the list of potential toxicants and may point toward a specific organ system and toxicant.3 It is invaluable to obtain and either test or store appropriate samples at the time of the physical examination or postmortem.
Blood should be examined for electrolytes, complete blood cell count (CBC), liver enzymes, blood urea nitrogen (BUN), and creatinine. Urine should be examined for specific gravity and discoloration, as well as crystals, casts, red blood cells, hemoglobin, and methemoglobin. Other body fluids (e.g., ocular, cerebrospinal), hair, and ingesta should be obtained as needed. All samples except blood and central nervous system (CNS) fluid can be frozen.3,6,7 Blood should be centrifuged, the clot removed, and the sample stored in the refrigerator. It is important to remember that zinc and many of the trace minerals must be collected in a special tube for analysis.6If possible, animals should be referred to the appropriate diagnostic laboratory for a postmortem completed by a board- certified pathologist. This is especially important if the animal is insured or legal issues are looming on the horizon. Animals sent to the diagnostic laboratory should be identified by tattoo, microchip, ear tag, or other means. Digital pictures taken before shipment can be used as a further source of identification. If a field necropsy is performed, extra samples should be taken because it is far wiser to take more samples than needed and discard them later rather than not have them at all. Often necropsy results will show specific lesions that may confirm a working diagnosis or point the veterinarian in another direction. Sometimes, the postmortem shows only generalized lesions or no lesions at all.