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.
Here is how it breaks down:
- 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".
- TH: Designates this Registry
number is for a (TH) Thyroid certificate.
- 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.
- 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
- F: Designates (M) Male or (F) Female.
- 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:
% Autoimmune Thyroiditis
% Idiopathic Hypothyroidism
OFA lists no information for Shetland
Sheepdogs at this time.
italicized words in purple can be found in the Glossary on the main Dog
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
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 fall into several categories—two types will be defined
by the registry:
- Autoimmune Thyroiditis
- Idiopathically Reduced Thyroid Function
Autoimme thyroiditis is known to be
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:
The method for classifying the thyroid status will be accomplished using
state-of-the-art assay methodology.
Indices of thyroiditis~
- 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
- 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.
- Thyroglobulin Autoantibodies (TgAA)—this procedure is
an indication for the presence of the autoimmune process in the dog’s
- FT4D within normal range
- cTSH within normal range
- Tg AAis negative
Positive autoimmune thyroiditis
- FT4D less than normal range
- cTSH greater than normal range
- TgAA is positive
Positive compensative autoimmune thyroiditis
- FT4D is within normal range
- cTSH is greater than or equal to normal range
- Tg AA is positive
Idiopathically reduced thyroid function
- FT4 D is less than normal range
- cTSH greater than normal range
- TgAA is negative
(All other results are considered equivocal)