OFA Thyroid

 

This is an actual copy of an OFA clearance for Thyroid. Inside the red box I have drawn on the certificate is the actual OFA registry number.  This number contains elements that give you detailed  information about this exam.

BF-TH20/23F-T

Here is how it breaks down:

 

 

  1. BF:  The first two letters of the OFA Registry Number are an indication of the breed of the dog.  In this case it stands for Bouvier des Flandres.  On an OFA certificate for a Shetland Sheepdog, the first two letters will be "SS".
  2. TH:  Designates this Registry number is for a (TH) Thyroid certificate.
  3. 20:  The next group of numbers before the slash indicate how many Bouvier des Flanders (or whichever breed of dog you are concerned with) have been screened for OFA Thyroid prior to this particular dog.  In this case, this dog is the only 20th Bouvier to have been screened for Thyroid abnormalities.
  4. 23:  This tells you this dog's age, in months, when the exam was completed.  This dog was 23 months old at the time of his OFA Hip exam.  12 months/1 year is the minimum age for a dog to receive this particular certificate.  This is an exam which is recommended to be repeated on approximately a bi-annual basis, at 2,3,4,6 & 8 years, as Thyroid is a system which changes during a dog's life.
  5. F: Designates (M) Male or (F) Female.
  6. T:  This tells you that this dog was permanently marked with some form of identification.  In this case, this dog was has a form of permanent identification. Effective January 1, 2001, the OFA has adopted a policy acknowledging animals that have been submitted for inclusion in our databases that have permanent identification in the form of DNA profile, microchip, or tattoo with a suffix of "-PI" instead of "-T".

    This letter signifies that the test was most likely performed on the dog listed on the certificate, but not all vets verify the dog's identification.  There have been cases where owner's have substituted dogs to obtain a certificate on a dog that, in fact, couldn't pass a health exam.  I want to hope that most people are basically honest and that we should question every certificate we look at - this is only a word of warning if you are already dealing with an individual with questionable morals.  As of January 1, 2001, OFA requires all dogs examined for certificates carry a permanent form of identificaiton.

The OFA site gives the following Thyroid statistics on the breeds raised at Moonstruck:

Breed
Evaluations
% Autoimmune Thyroiditis
% Idiopathic Hypothyroidism
% Equivocal
Bouvier des Flandres 335 3.3 0.9 11.9
Shetland Sheepdog OFA lists no information for Shetland Sheepdogs at this time. 

 

**All italicized words in purple can be found in the Glossary on the main Dog Health page.**

The following description of Thyroid is taken directly from the OFA site:

Autoimmune thyroiditis is the most common cause of primary hypothyroidism in dogs. The disease has variable onset, but tends to clinically manifest itself at 2 to 5 years of age. Dogs may be clinically normal for years, only to become hypothyroid at a later date. The markers for autoimmune thyroiditis, autoantibody formation (autoantibodies to thyroglobulin, T4 or T3),usually occur prior to the occurrence of clinical signs. The majority of dogs that develop autoantibodies have them by 3 to 4 years of age. Development of autoantibodies to any time in the dog’s life is an indication that the dog, most likely, has the genetic form of the disease. Using today's technology only a small fraction of false positive tests occur.
     As a result of the variable onset of the presence of autoantibodies, periodic testing will be necessary. Dogs that are negative at 1 year of age may become positive at 6 years of age. Dogs should be tested every year or two in order to be certain they have not developed the condition. Since the majority of affected dogs will have autoantibodies by 4 years of age, annual testing for the first 4 years is recommended. After that, testing every other year should suffice. Unfortunately, a negative at any one time will not guarantee that the dog will not develop thyroiditis.
     The registry data can be used by breeders in determining which dogs are best for their breeding program.  Knowing the status of the dog and the status of the dogs lineage, breeders and genetic counselors can decide which matings are most appropriate for reducing the incidence of autoimmune thyroiditis in the offspring.
Thyroid Abnormalities~

Thyroid abnormalities fall into several categories—two types will be defined by the registry:

  1. Autoimmune Thyroiditis
  2. Idiopathically Reduced Thyroid Function
 
Autoimme thyroiditis is known to be heritable!

Equivocal results~
Those dogs with laboratory results that are questionable, therefore not definitive, will be considered as equivocal. It is recommended that the test the repeated in three to six months.

OFA Thyroid Certification:


Classification~
The method for classifying the thyroid status will be accomplished using state-of-the-art assay methodology.

Indices of thyroiditis~
  1. Free T4 by dialysis (FT4D)—This procedure is considered to be the "gold standard" for assessment of thyroid's production and cellular availability by thyroxine. FT4D concentration is expected to be decreased in dogs with t hyroid dysfunction due to autoimmune thyroiditis.
  2. Canine thyroid simulating hormone (cTSH)—this procedure helps determine the site of the lesion in cases of hypothyroidism. In autoimmune thyroiditis the lesion is at the level of the thyroid and the pituitary gland functions n ormally. The cTSH concentration is expected to be abnormally elevated dogs with thyroid atrophy from autoimmune thyroiditis.
  3. Thyroglobulin Autoantibodies (TgAA)—this procedure is an indication for the presence of the autoimmune process in the dog’s thyroid.
 

Certification~

Normal
  1. FT4D within normal range
  2. cTSH within normal range
  3. Tg AAis negative
 

Positive autoimmune thyroiditis

  1. FT4D less than normal range
  2. cTSH greater than normal range
  3. TgAA is positive
 

Positive compensative autoimmune thyroiditis

  1. FT4D is within normal range
  2. cTSH is greater than or equal to normal range
  3. Tg AA is positive
 

Idiopathically reduced thyroid function

  1. FT4 D is less than normal range
  2. cTSH greater than normal range
  3. TgAA is negative
 

(All other results are considered equivocal)

OFA Hips OFA Elbows CERF OFA Thyroid OFA Cardiac von Willebrand's Bloat (GDV) Study Dog Owner's Reference