What do Blood Tests Tell Your Veterinarian?

December 18, 2014

bloodwork vialsVeterinarians at The Animal Medical Center must say “Let’s send some blood to the lab” about 100 times a day. But what are we looking for in all those tubes of blood with the colorful stoppers?

CBC = Complete Blood Count
Your dog’s or cat’s blood contains at least four types of white blood cells, red blood cells and blood clotting cells, called platelets. A complete blood count analyzes what cells are present, how many cells of each type make up the blood sample, and identifies any unusual cells present. For example, the presence of increased numbers of immature white blood cells, called band neutrophils or bands for short, indicate a serious infection. Last week, one of my patients had an elevated total white blood cell count and 1,236 bands per microliter of blood; normal is less than 300. An abdominal ultrasound determined she had a gallbladder infection.

In addition to assessing the types and numbers of white blood cells, the CBC measures the number of red blood cells and several different features of them as well. A lack of red blood cells is called anemia, and too many red blood cells suggests a rare hematologic disorder called polycythemia. Size is a critical diagnostic feature of red blood cells – too big and we look for an increase in baby red blood cells responding to bleeding or anemia; too small and we worry about iron deficiency. The amount of hemoglobin (oxygen carrying protein) is measured as well. If there is too little hemoglobin, we worry about iron deficiency, and red blood cells are so smart they never synthesize too much hemoglobin. If the lab report indicates the hemoglobin is elevated, we scrutinize the sample for possible errors.

Chem Panel = Serum Biochemical Profile
The CBC looks at the whole blood sample in pretty much the same form as it circulates in the bloodstream. Serum is the liquid portion of the blood without the blood cells. Serum is produced in the lab by spinning the blood in a centrifuge and using a pipette to remove the liquid portion. The serum sample is used to run a serum biochemical profile, a series of 20 or so tests that come in a panel.

The chem panel can be divided up into several different organ systems. Some tests increase with liver disease like the alanine amino transferase, or bilirubin. When a patient has a kidney problem, we often see elevations in blood urea nitrogen and creatinine. Then there is a group of tests that analyzes the concentration of chemical elements like calcium, phosphorus, sodium, potassium and chloride in the blood. These analytes are important for cellular function and can be abnormal in a wide variety of diseases, like adrenal gland diseases, kidney disease and urinary blockage. Typically a chem panel includes measurement of the protein level in the blood. Protein is affected by a wide variety of conditions and is usually interpreted in concert with the other abnormalities found in the panel. Finally, the chem panel measures blood sugar when looking for diabetes or low blood sugar.

The Combination is Critical
Submission of a CBC and chem panel is so routine that it is test #1 in The AMC’s lab ordering system! When paired, these two tests become a powerful tool for veterinarians to assess the health of your pet or to direct further testing to identify the cause of your pet’s illness.

Fun Things Blood Tests Can Tell Us
Blood tests don’t only tell us about disease, but also can give us other little tidbits about your pet:

  • If you have a mixed breed dog, a blood test analyzing your dog’s DNA can tell you about his parents and what breeds are in his genetic makeup.
  • Avian specialists use a blood test to tell if your bird is a boy or girl.
  • A blood test can also be used to predict the birth of a litter of puppies. A rise in blood progesterone to 2-3 micrograms/ml occurs 63 to 65 days prior to whelping – the dog word for birth of puppies.

ABC’s of Feline DNA

November 10, 2011

Nearly everything about us and our cats is determined by a molecule called DNA (deoxyribonucleic acid).  Due to the wonders of molecular genetics, DNA has been harnessed as a method of diagnosing diseases in our feline companions. Because members of a breed are closely related, genetically based diseases are often first identified in a family of purebred cats.  Purebred cats, such as those you can meet at the 2011 AKC Meet the Breeds show at the Javits Center in New York City on November 19 and 20, have contributed to the advancement of DNA testing – testing benefitting all cats.

DNA and Disease
Ragdoll and Maine Coon cats may both develop cardiomyopathy, a disorder of the heart muscle causing the muscle to become very thick and resulting in heart failure. Analysis of the DNA in these two breeds has identified mutations associated with the development of hypertrophic cardiomyopathy. Breeders often use this test to help select the healthiest cats to parent future litters of kittens. The AMC’s Cardiology Service does not use this test to predict the development of cardiomyopathy because all cats with the mutation do not go on to develop this type of heart disease. The AMC’s staff cardiologists, Dr. Betsy Bond and Dr. Philip Fox, perform echocardiography to diagnose cardiomyopathy in cats.

The red blood cells of the Abyssinian cat and its cousin, the Somali, are affected by a genetic disease called pyruvate kinase deficiency. The enzyme pyruvate kinase can be found in the biochemical pathway responsible for providing the red blood cell with energy. Cats lacking this enzyme have weak red blood cells. The shortened survival of these weakened red blood cells renders affected cats sick and anemic. Domestic cats have also been diagnosed with this genetic disease.

Chronic upper respiratory infections and chronic diarrhea result from infection with a variety of organisms. DNA testing can be used to determine the cause. DNA testing identifies the presence of DNA belonging to a disease-causing virus, bacteria, parasite or mycoplasm, thus determining the cause of infection and directing therapy.

Conducting DNA Testing
DNA testing can be performed on a variety of samples. The sample submitted to the laboratory by your veterinarian will depend on the test being performed. If the test is looking for a mutation in your cat’s DNA as the cause of a disease, cardiomyopathy, for example, the sample must contain your cat’s DNA. Cheek swabs and blood samples are typically submitted for this type of test. If your veterinarian is looking for an infectious organism, the site of the infection might be sampled. A conjunctival swab can be used to detect feline upper respiratory viruses; feces can be used to identify the causative agent of diarrhea. Some tumors carry genetic mutations and the actual tumor sample is submitted to the laboratory to identify the mutation and the type of tumor.

Meet Purebred Cats
To meet all the purebred cats I have highlighted in the blog and more, join us at the 2011 AKC Meet the Breeds show at New York City’s Javits Center on November 19-20.  Billed as an event where families can meet 160 dog breeds and over 50 cat breeds, the event promises to have something for everyone. Don’t miss this great opportunity to meet wonderful purebred cats, ask questions about them, and learn which one is the best one for your family. Stop by the Animal Medical Center booth to say hi! You can meet some of the staff and veterinarians who work with us and ask questions about your cat’s health.

Image: Elizabeth and Moby. See adorable purebred cats like these at AKC Meet the Breeds®
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This may also be found in the “Tales from the Pet Clinic” blog on WebMD.com.

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit www.amcny.org. To make an appointment, please call 212.838.7053.


Everything Old is New Again: Plague and Leprosy

July 7, 2011

Nine banded armadillo, which can carry leprosy, seen in Brooklyn’s DUMBO neighborhood at modern:ANTHOLOGY.

Last week there were two very interesting stories in the news about the intersection between people and animals. Both reported on diseases we rarely hear about anymore: plague and leprosy.

Leprosy is the older disease and has been reported since Biblical times. The first reported epidemic of plague occurred somewhat later, in the 6th or 7th century. Bubonic plague, or the Black Death, was the scourge of the Middle Ages.

Plague is an infectious disease caused by the bacteria Yesinia pestis. The usual source of Y. pestis is the rat flea, but hunting pets can contract the plague from eating infected rodents or rabbits. Even though Y. pestis is predominantly found in California, Utah, New Mexico, Arizona and Nevada, cases can be seen throughout the country if a human or pet travels to one of these areas and contracts the disease before they return home. An infected pet can, in turn, infect humans. The possibility of plague transmission is one reason prairie dogs may not make the best pets.

The name bubonic comes from the word bubo, which is a fancy word for enlarged lymph node. Wikipedia shows an illumination from a medieval Bible of sinners afflicted with buboes.

Both humans and pets with bubonic plague have enlarged lymph nodes, which are painful. Fever, malaise and non–specific flu-like symptoms are typical for plague in both humans and pets. Although last week’s plague case occurred in a dog, in general, cats are more susceptible to plague than dogs.

Leprosy was in the news too; not because of a sick dog or cat, but because of armadillos. Those prehistoric-looking armored mammals carry the leprosy bacteria, Mycobacterium leprae. Most leprosy cases occur outside the United States, but cases occur in people who have not traveled outside the USA. This finding puzzled researchers until the DNA of the M. leprae was studied. Both armadillos and humans infected with M. leprae in the USA share the same unique strain of the bacteria. This bacterium is different from the strain of M. leprae found outside the USA. The New England Journal of Medicine article concluded humans can contract leprosy from infected armadillos.

To help protect yourself and your pet from contracting diseases of wildlife:

  • Keep your pet leashed or indoors to prevent contact with wild animals which can cause serious diseases.
  • Never approach, pet or handle wildlife even if they are acting friendly.
  • If your pet is sick, always tell your veterinarian where your pet has traveled and do the same when you visit your physician. It may be just the perfect clue to the diagnosis.

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This may also be found in the “Tales from the Pet Clinic” blog on WebMD.com.

For over a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center, 510 East 62nd Street, New York, NY 10065. For more information, visit www.amcny.org. To make an appointment, please call 212.838.7053.


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