The Veterinary Diagnostic Laboratory System
As I write this article, we are approaching the end of fiscal year 2014. I was just reviewing some numbers for the year. When I was in private veterinary practice, I suppose I sat down and totaled the number of fecal exams, pregnancy checks, equine castrations and so on that I did. Any good manager needs to be able to analyze what they are doing, and know if what they are doing is justified profitably or for other justifiable reasons.
If you work for the government, it is important to be able to justify how you are spending the taxpayer’s money. I am a taxpayer myself, so I do not have a problem with reporting up the line what we are doing and how we are spending those tax dollars.
Anyway, to get back to the subject at hand, when I looked at the numbers coming out of our diagnostic laboratory system, I was pretty impressed at what we do to support the pet, veterinary, poultry and livestock industries. It’s not like it was a great revelation to me or even that some light came on that made me aware of the volume of tests, examinations and reports coming out of our veterinary diagnostic laboratories. We have all heard of the $700 hammers and other government waste that occurs. I just want you to know how well we spend your and my tax dollars at our diagnostic laboratories.
Collectively, our main laboratory at Auburn and the branch laboratories log in about 35,000 cases annually. Now, some of those cases may be a single blood sample that needs to be tested for a certain disease, but even the single blood sample will be tested for several different diseases. Some of these cases may be examining a biopsy from a lump your veterinarian took off your dog’s face. Many of those cases account for full necropsies (autopsies to the rest of the world) on dogs, cats, chickens, horses, cows, bulls and an occasional pet iguana or pet snake. Many of the cases involve multiple tests that take multiple personnel to help arrive at a diagnosis. We provide testing in the areas of microbiology, virology and molecular testing, toxicology, parasitology, serology (alone runs over half a million tests), clinical pathology and histology. Those are the main functions of the laboratories. But sometimes there may be a less common test that is needed and we have to package the sample and ship it to another laboratory that does perform the specific needed test.
There is a fair amount of work that goes into each case. Even with the single blood sample, someone in receiving has to open the box it was shipped in, make sure the information is correctly logged in and then make sure the sample gets to the serology section at the lab. In the serology section, even to run a single test on a single sample of serum, the reagents must be tested with controls at least daily – sometimes more often – to make sure our tests are accurate. While the results of some tests may be read immediately, many tests take some period of time before the results are final. All along the way, the paperwork must follow the sample to make sure the report is accurate as well as reported for the correct sample. If the sample is negative, the serum sample is often kept for a period of time in case other tests may be needed later for some reason. These animals are often dead and going back to collect more blood from them is simply not an option.
When a full necropsy is involved, the whole process often involves most sections of the laboratory and several people to be involved in a single case. Typically, whether a necropsy is performed at one of the branch labs or at Auburn, one of our veterinarians goes over the carcass with a fine-tooth comb looking for abnormalities that can be seen with the naked eye. Often samples are cultured to determine if a bacteria or fungus was involved in the sickness and death of the animal. There may be certain blood tests that can be performed at the branch laboratories that are sometimes sent to Auburn to be confirmed by a more specific test. Sometimes the necropsy points in a specific direction. Sometimes it points in a general direction. Sometimes nothing looks abnormal at all visually. On those occasions the histological examination, virology and toxicology tests become even more important.
Sometimes, this clinical history an owner gives us is that the animal seemed to have trouble breathing. When the lungs are examined during the necropsy, it may be obvious that the animal had bacterial pneumonia. Then maybe the microbiologist cultures the bacteria Manhiemia hemoliticafrom the lungs. That is the bacteria associated with shipping fever in cattle. Maybe the calf has just come through a stockyard or has experienced other stresses recently that may have contributed to pneumonia. We will do an antibiotic sensitivity test that helps us recommend the most appropriate antibiotic to us if other calves are diagnosed with pneumonia in close proximity to the one necropsied. Then our case may be closed. But maybe the calf had been in the same pasture for six months, lived a pretty dull life and there were no obvious stress factors that could have led to pneumonia. At that point, we work to find out if there is an underlying virus that may have been involved in the pneumonia or some factor that our lab may find that suppressed the immune system. With weaned calves selling for well over $1,000 each, that kind of information can be extremely valuable to the producer.
In other cases, where the carcass looks normal or near normal on the necropsy, the histological examination and other tests become extremely important. The word histology can be broken down into hist, meaning "tissue," and logos, meaning the "study of" – thus the study of tissue. To perform a histological examination, tissues are sliced very thin, stained and fixed on a microscope slide. The slide is examined carefully to determine if the tissue is diseased and, if so, what type of disease may be present.
Maybe we watch "NCIS," "CSI," "House," "MD" or other shows where the illness, diagnosis and treatment take place in an extremely formatted 60-minute time slot. I can assure you, it generally doesn’t work that way. And while we have been affected by budget cuts and work with less personnel than would be optimal, the approximately 50 or so employees of our diagnostic laboratory system are working hard to get you, your veterinarian or your neighbor an accurate diagnosis. We continue to work to make our turn-around time better. Still, when I see the approximately 35,000 cases, hundreds of thousands of tests and the number of people doing the job, I am satisfied we are doing our best to give the taxpayer his or her money’s worth.
Dr. Tony Frazier is the State Veterinarian for Alabama.