Function Of The Thyroid
	The sole purpose of the thyroid gland is to convert dietary iodine into two thyroid hormones T4 and T3. When thyroid hormones become abnormal, many, if not all body systems are also affected. Thryoid disfunction compromises the immune system leaving the dog susceptible to all types of illness.

The thyroid gland produces thyroid hormone in a mechanism by which it combines the element iodine with the amino acid tyrosine. In this process, one or two iodine molecules attach to a tyrosine molecule to form iodinated tyrosines (iodotyrosines). Compounds containing one iodine or two iodine molecules then combine with one another in a process known as coupling to form the primary thyroid hormones, T4 (tetraiodothyronine or thyroxine with 4 iodine molecules) and T3 (triiodothyronine with 3 iodine molecules).

Normally, the thyroid gland secretes an abundance of T4 along with smaller amounts of T3 and even smaller amounts of tyrosine, T1 and T2. When T4 reacts with the cells that comprise the body's organs, including the pituitary, liver, brain, and skeletal muscle, it loses an iodine atom to become T3. The majority of T3 found in the blood circulation is formed by this peripheral (away from the thyroid gland) conversion of T4 to T3. T3 is approximately 10 times more potent than T4, although both T4 and T3 serve vital functions. And consequently most of the T3 found in the blood is produced from peripheral conversion of T4 into T3.

Testing Thyroid Function

Neighborhood Veterinary offices do not run thyroid tests themselves. They draw the blood and then send the sample to a laboratory to run the tests and send the results to the veterinarian. Laboratories vary in quality and experience. Most Vets will read the test, and as long as the results fall anywhere in between the laboratory's "Normal Range" they will tell you (and believe) that the dog is not Hypothyroid. This is one reason why it is very important that you understand how to analyze the test results to determine if your dog has "Borderline" or Sub-Clinical" Hypothyroidism. Dr. Jean Dodds at Hemopet is foremost in the field of thyroid testing and is who I recommend for these tests. Dr. Dodds will run the test and provide interpretation of the results using breed specific data and data that you provide on the forms submitted with the sample.

Preparing For The Thyroid Test
	Sexual activity/hormone fluctuations affect thyroid health. Hormone fluctuations affect not only thyroid, but hip laxity. Thyroid "normals" vary by breed, age, performance level, etc. General "normals" are meaningless. Test intact bitches 12 - 16 weeks AFTER day 1 of the previous cycle. Animals should be fasted for 12 hours prior to drawing blood for the test.

Six Panel Thyroid Test
	The six panel thyroid test examines your dogs Thyroid feedback system. You must ask specifically for this test in order to get the data you and your vet need to analyze the results. A six panel test includes Total T4, Total T3, Free T4, Free T3, T4 antibodies, and T3 antibodies. Anything less than a six panel test does not give you Total Thyroid Function.

How To Analyze Thyroid Panel Results

The first thing you need to do is calculate the 50% mark of the "Normal Range" for each panel. (Total T4, Total T3, Free T4, Free T3, T4 Antibodies, T3 Antibodies. Each panel will have a "Normal Range" associated with it. To calculate the 50% point you add the end values of the range and divide by 2. If your dog falls below the 50% mark of these ranges, you should speak to your vet about supplementing your dogs thyroid.

Examples of Calculation
	Total T3 Lab "Normal Range" = 1.0 - 2.5 Add end values together (1.0+2.5 = 3.5) Divide result by 2 (3.5/2 = 1.75) 50% of the "Normal Range" = 1.75