Thyroid function test and pets.: I have received... - Thyroid UK

Thyroid UK

111,357 members129,489 posts

Thyroid function test and pets.


I have received a copy of the letter that the specialty doctor sent to the ENT surgeon regarding me having surgery for an over active thyroid which is only just over but I have been feeling very ill. It says as follows - The likely reason for the discrepancy between the symptoms and biochemical parameter may be due to the fact that she is keeping pets at home and this is a well known factor as it can cause profound discrepancy in the outcome of the thyroid function test.

Has anyone ever heard this before please?

29 Replies

Rosie2-2, I've never heard of such a thing. The letter wasn't dated 1st April was it? If it's true I'd love to know how keeping pets affects thyroid function test outcomes.

Rosie2-2 in reply to Clutter

Well the ENT consultant said he had never heard such a thing, I have googled it and there is nothing on there.

Clutter in reply to Rosie2-2

Rosie2_2, what sort of specialist was the doctor who wrote to the ENT?

Rosie2-2 in reply to Clutter

On the letter is say Specialty Doctor in Diabetes and Endocrinology.

Oh my goodness!! I knew animals have healing powers but being the cause of thyroid symptoms is a new one on me!! I'd want to see a different thyroid specialist. Crazy, crazy......

Sorry keeping pets affects thyroid tests????? Wonder what this specialist has been reading......

LAHs in reply to waveylines

I wondered what she was smoking!

i have read and been told some utter nonsense by drs but this is new to me, of course i should have guessed its all my dogs fault my thyroid was removed and was left untreated pfft

I wonder if the supposedly specialty supposed doctor was from a background that considers pets/dogs to be unclean and is on some mad, species-ist vendetta? What an utter load of tripe - the latest research is proving that the presence of animals in the first years of a person's life not only strengthens the immune system but also protects against the development of asthma,


Interference with tests is a well-known issue albeit, that issue is so very often ignored or swept under the carpet.

A) If true, then around 50% of all thyroid function tests are useless. (A quick grab found a statistic of 48% of UK households have pets. Big assumption by me that TFTs are split evenly across all households.)

What on earth are these consultants doing making treatment decisions on FTFs that have been affected by pets?

B) If NOT true, why has the specialty doctor written that?

Here is a substantial paper, in full, from 2013 about factors which influence and interfere with TFTs:

It contains this passage:

Assay interference

TSH measurement

Most commercially available TSH assays are based on an immunometric two-site (or ‘sandwich’) format with capture and (labelled) detection antibodies directed against different epitopes on TSH, with the analyte essentially acting as a bridge between the two (Fig. 4a). The capture antibody is typically immobilized to a solid phase to ensure good separation between bound and unbound label, thus increasing sensitivity; often, several different detection antibodies are employed to further improve assay sensitivity. The presence of human anti-animal antibodies (HAAs) in a patient's serum can interfere with TSH measurement if directed against the same species as the assay antibodies: thus, a HAA that is capable of cross-linking the capture and detection antibodies may cause ‘positive interference’, leading to a falsely high TSH (Fig. 4b); conversely, a HAA that blocks TSH binding to either capture or detection antibodies will result in ‘negative interference’, causing a falsely low TSH readout (Fig. 4c). Many manufacturers now include panels of antigens or pre-immune serum from source animals in an attempt to ‘mop up’ HAAs. However, heterophile antibodies (which are weak, polyspecific antibodies that are similarly capable of causing negative or positive interference) can prove more difficult to remove. Such interference in the TSH assay may be seen in cases of Graves' disease and in patients with positive rheumatoid factor (RhF), although emerging evidence suggests that the finding of a raised RhF titre in this context may in itself reflect heterophilic antibody interference in the RhF assay (Chatterjee, Halsall & Gurnell, unpublished data). Interfering antibodies can also bind the analyte (TSH) rather than the assay antibodies. An extreme example of this type of interference is the ‘macro hormone’ complex, in which a specific anti-TSH immunoglobulin binds TSH and neutralizes its biological activity, but leaves epitopes exposed for interaction with the assay antibodies. The consequence is analogous to artefactually elevated prolactin concentrations seen in patients with macroprolactinaemia. If interference is suspected, it is best to seek the advice of the laboratory as there are several ways to confirm this, for example by demonstrating:

• varying TSH results in assays that utilize different antibody pairs or incubation times,

• a different TSH result following manoeuvres [using polyethylene glycol (PEG) or protein G/A treatment of sample] that remove the interfering antibody,

• nonlinear TSH measurement following sample dilution: if either TSH or the assay reagents are weakly bound by interfering antibodies this interaction may be disrupted by dilution and a nonlinear dilution series will result. [More by following link above... ]

So it appears that there is the possibility of human anti-animal antibodies interfering. But how does presence of human anti-animal antibodies which affect FTFs correlate with pet ownership?

Many of us have unwitting or non-pet contact with animals. Obvious examples: anyone in the animal industries (farmers, vets, abbattoir workers, butchers), or animal product industries (tanning, taxidermy), patients who have been treated with various substances created in animals. Why pick on pet-keeping alone?

The simple quoting by this specialty doctor that there is interference is completely useless. If that appears possible, then follow procedures (some of which are identified in the paper) to eliminate interference.

greygoose in reply to helvella

Well, that sounds to me like another reason why TSH testing is useless - or next to useless. What about the FT4 and FT3? Are they affected too? If not, why aren't more doctors/endos using those measurements to diagnose/treat if the effects of 'pets' on the TSH is so well-known?

And that, Rosie, is the question you should be asking your doctor. :) I'd love to see the look on his face! lol

helvellaAdministrator in reply to greygoose

Go to the paper - it goes on to mention T4 and T3 next...

(I thought my post was long enough already. :-) )

Rosie2-2 in reply to greygoose

I am waiting for an appointment for a scan, I hope that my pets don't give any discrepancies in that, lol

Rosie2-2 in reply to helvella

This doctor comes from Sudan, he would never have known I have pets if I had not asked him how RAI would affect my pets, which he didn't know any way. So what would he have blamed if I hadn't mentioned my pets. He looked at me like I was stupid, I could read his mind.

belford in reply to Rosie2-2

you have just answered the question of why a doctor would say that it is common in the Sudan and many other countries for them to think dogs are only good for one thing namely eating in other parts of the Sudan they are considered dirty animals

Take Mugabe (I know he is not from the Sudan) he had all the dogs killed especially the ridge back and they were the one dog that would kill a lion if it had to to defend its owner

LAHs in reply to helvella

Well, looking on the bright side at least she has a doctor who reads the literature. S/he may be interpreting it a bit wackie but at least s/he is trying.

Clutter in reply to LAHs

LAHs, I'd find it extremely trying if my endo told me discrepancy between the symptoms and biochemical parameter was due to me keeping pets.

LAHs in reply to Clutter

Yes, more than trying - calls for a change of doc. I've just got back from having a chat with my 6 cats, 3 chickens and 2 peacocks.

Clutter in reply to LAHs

LAHs, my 2 dogs think the endo is barking mad and in need of kennel rest.

belford in reply to LAHs

My 6 cats all looked at me as if I was mad when I told them about it wonder if that doc really did translate the passage in that paper the wrong way it sure looks as if he/she did now think about what they said if you cannot understand the doctor or the doctor mixes things up whch it looks as if he has done then he has to be reported to the powers that be you never know he might even diagnose an animal as having a thyroid problem brought on by contact with humans

With five dogs, a cat, nine ponies and a multitude of chickens I can only surmise from this information I am doomed! 😜

MrsRaven in reply to Nickinoo1

Nickinoo, you arent the only one. Ive got a small zoo here, everything from 4 dogs and three cats, to 35 guinea pigs, ferrets, around 100 snakes and too many rodents to count. I have always kept and worked with animals, since I was a small child, but I have only had thyroid problems for the last 25 years, when I had many less animals.

Rosie2-2 in reply to MrsRaven

At least he has given us a laugh.

belford in reply to Nickinoo1

you lucky so and so having all that lot bet they can do a lot as well now make sure you do not stop their thyroid working (just thought Id take the mickey in the last few words)

There has been a link with keeping pets with multiple sclerosis, maybe he's got them mixed up? All in all not someone you would want to keep seeing.

Short answer, no!

Sounds like another cop-out to me!

whenever the medical profession cannot find out what has made a thing like a thyroid go wrong they will blame anything and everything no matter what harm it may cause by their doing this I can bet no one ever mentions the Russian nuclear accident I was lucky so to speak as I did have a good doctor he straight away told me a lot of people were having trouble with their thyroid after the Russian nuclear power station blew up the fall out from that reached the Uk and if the docs tell you it did not they are definatly telling a load of lies My dad if he were alive today would tell you where his cancer came from my mother would tell you why her thyroid became useless after never having a problem with it this happened after the Russian nuclear power station blew up I never had pets prior to loosing my thyroid I had to have mine taken out and what made me smile about that was my specialist told me what caused mine was the Russian power station then he told me that they were going to give me more radiation to destroy the thyroid he was adament what caused mine I now do have cats and 2 or 3 of the 6 cats I have will always tell me if I am going to have a seizure by jumping onto my wheelchair to warn me they do a lot of things for me so do not let any untrained human doctor tell you something that any vet will tell you is a load of rubbish the benefit of having a pet far out weighs a heck of a lot of things

It makes you wonder whether some of these Endocrinologists' make it up as they go along, so frustrating for you 😐

You may also like...