Blood Profiles for Iditarod Dogs

by Angie Hamill, Health Event Coordinator, Providence Laboratory Services, and Stuart Nelson, Jr., DVM, Chief Veterinarian

I would like to dedicate this article to the topic of sled dog blood testing. For the past few years, Providence Alaska Medical Center Laboratory Services provided this service to all dogs preparing to enter the Iditarod Trail Sled Dog Race. Angie Hamill, Health Event Coordinator, Providence Laboratory Services, has played a key role in making this happen, for which I am very grateful. The testing has increased the health care for our world-class canine athletes to an unprecedented level, and I am optimistic that more races will implement similar programs.

Pre-race blood testing is offered on a voluntary basis during the December prior to the race start. All dogs must be tested in February to be eligible for the race in March. A complete chemistry and hematology panel is performed in the laboratory and results are sent to both the musher and the chief veterinarian of the race for review. The blood test results are valuable tools in the decision making process when deciding which dogs will be chosen for an Iditarod team. In preparation for the 2001 Iditarod Sled Dog Race, Providence Laboratory performed blood testing and provided results on over 2100 dogs.

Planning for the blood collection and testing begins months prior to the race start. Iditarod Head Veterinary Technician, Lynette Perrine, schedules a date, location and time for each musher to bring in their dogs for collection of the blood samples. From the laboratory, supplies are ordered to cover the blood collection and bar code labels are pre-printed for use on each tube of Iditarod dog blood. Racks and boxes are prepared for transporting the blood samples from the collection site to the laboratory.

In both December and February, mushers arrive with their dogs at the designated collection site to have the blood samples collected by one of the Iditarod veterinary technicians. Once collected and labeled, the tubes of blood are placed in racks and packaged for delivery to Providence Laboratory. A data sheet listing pertinent information on each dog is completed and included with the specimens.

Upon arrival of the specimens in the laboratory, information on each dog is entered into the computer. This data includes musher’s name, dog’s name, dog’s age, sex and microchip number, date of collection and tests to be performed. Once testing is ordered, highly skilled medical laboratory technicians and medical technologists analyze the specimens. Both Coulter and J&J Vitros instruments are used in the analysis.

The following is a brief description of the significance of the various tests. Volumes have been written on this subject matter, so this is by no means all-inclusive. However, it should at least give some guidelines for reference. WBC – White Blood Count refers to the number of white blood cells circulating in the blood. White blood cells are a group of several types of cells produced primarily by the bone marrow and lymph nodes for the purpose of fighting infection and inflammation in the body. Increased values typically indicate infection, inflammation or stress. Low values may indicate blood loss (bleeding) or certain types of bone marrow disorders (leukemia). Values change on a daily basis.

Hematocrit is a measure of the red blood cell concentration in circulating blood. The purpose of red blood cells is to carry oxygen to the other cells of the body. Low values indicate anemia (decreased red cells), typically as the result of reduced production by the bone marrow, increased destruction of red cells (autoimmune diseases) or blood loss. The latter could be associated with a bleeding stomach ulcer. High values may be associated with dehydration (loss of circulating fluid volume) or an abnormal increase in production by the body. It normally takes at least three weeks for an animal to build a low red blood count back up to the normal range after the cause of the anemia is corrected.
Hemoglobin is the oxygen carrying substance in red blood cells. Low and high values are usually a result of the same abnormalities that affect hematocrit readings, although some nutritional deficiencies more seriously reduce hemoglobin values.
Mean Corpuscular Volume refers to the size of the red blood cells. This is particularly useful in trying to classify an anemia that may be present. More immature (newer) red blood cells are larger than older ones.
Platelet Count refers to the number of platelets present. A platelet is a type of cell produced in the bone marrow that initiates the clotting mechanism. Low values are usually the result of chronic bleeding, although bone marrow disorders and autoimmune diseases are other potential causes. High values are rare.
These are electrolytes which are very important in the proper functioning of all cells, but especially nerve and muscle. Abnormalities can be caused by many conditions, including kidney and adrenal gland disorders, and any illness that results in vomiting and/or diarrhea. Vomiting and diarrhea can lower these values as the result of loss through the GI tract, which is why supplementation of the diet with electrolyte preparations is recommended as part of the treatment of such conditions.
Glucose is a measurement of the circulating blood glucose (sugar) level. Low levels (hypoglycemia) are uncommon, but may be associated with metabolic abnormalities and/or too infrequent feeding in some performance animals. High levels can be due to excitement, eating foods supplemented with dextrose or other sugars within a couple of hours of testing, diabetes, stress or illness.
Total Protein is the sum of the types of protein circulating in the blood. Low values may be associated with parasitism, abnormalities in liver, kidney or intestinal function, and/or nutritional problems. High values may indicate dehydration, chronic illness or inflammation.
Albumin is normally the most common type of protein found in the blood. Low values may result from decreased production (parasitism, liver disease, chronic illness, malnutrition) or increased loss through the kidneys and/or intestinal tract. Globulin is the other major component of Total Protein. This value is determined by subtracting the value for albumin from that of the Total Protein. Globulins are the proteins also known as “antibodies,” the purpose of which is to combat infections.
These are important minerals, which are critical for nerve and muscle activity. Abnormalities may be due to parathyroid, kidney or bone disease, lactation or to extreme nutritional imbalances.
These are waste products of protein metabolism which are excreted by the kidneys. BUN (Blood Urea Nitrogen) values vary more on a day-to-day basis than do those of creatinine. Low values are uncommon, but may be associated with liver disease. High values may be due to very high protein diets, strenuous exercise, dehydration and/or kidney disease.
Bilirubin is a waste product from the breakdown of hemoglobin from red cells. Bilirubin is formed in the liver and excreted through the bile ducts and gallbladder into the intestine. Low values are not significant. High values can be due to liver disease, bile duct abnormalities or increased breakdown of red cells.
ALKaline PHOSphatase is an enzyme found primarily in the bone, and intestine. Low values are not significant. Higher values usually indicate inflammation in one or more of these areas. Elevated levels may also be normally present in growing and pregnant dogs.
Creatinine Kinase is an enzyme specific to muscle tissue. Low values are not significant. Elevated values indicate muscle injury or damage.
Serum Glutamic Oxaloacetic Transaminase and Aspartate aminoTransferase are different names for the same enzyme. This enzyme aids in various chemical activities primarily within the cells of muscle and liver tissues. Low values are not significant. High values indicate abnormalities in one or both of these tissues.
Serum Glutamic Pyruvic Transaminase and Alanine aminoTransferase are also different names for the same enzyme. In dogs, this enzyme is regarded as liver specific. Low values are not significant. Increased values are indicative of a liver abnormality.

The following is an established list of normal blood values for sled dogs as determined by blood sampling of all potential competitors prior to the past four Iditarod Sled Dog Races.

WBC TH/mm3 4.5-16.0
MCV u3 64-74
PLATELETS TH/mm3 100-380
SODIUM MEQ/L 139-147
ALBUMIN G/DL 2.9-3.7
CALCIUM MG/DL 9.3-10.9
BUN MG/DL 12-34
ALK PHOS IU/L 20-140
CK TOT IU/L 50-1700
SGOT IU/L 20-103
SGPT IU/L 30-17

Many hours are dedicated to analyzing the specimens for the full profile. Once each day’s specimens are completed, all results are reviewed and checked for any values that may warrant the need for immediate attention. Any critical results are faxed or called to the chief veterinarian, who will then contact the musher to discuss the findings. Copies of each team’s results are mailed to both the musher and chief veterinarian.

By performing all of these blood tests we can learn a great deal about the health of our sled dogs. It is a great tool for both mushers and veterinarians alike to utilize in their kennel management. It takes a great team of dedicated coordinators, veterinary technicians, data entry personnel, clinical laboratory assistants, medical laboratory technicians, medical technologists and veterinarians, as well as the financial support of Providence Laboratory Services, to make this blood testing for Iditarod dogs available.