What Is Involved In A Thyroid Test?

[cannibalgoldfish]

Is it just a blood test? Nothing drastic? Vet said one of my dogs has either seasonal contact allergies or a possible thyroid problem. This is a new vet since the old one kept saying my dog was fine. Well, he isn't. Before I changed vets I had a suspicion about it being a thyroid problem so I would like to get him checked. But what is involved? Yes, I will be getting it done anyway but I would like to know for budget reasons what expenses I would be looking at?

[Perry's Mum]

Just a blood test but when I had it done for Amber my last dog it was done twice - once to check levels and then a few weeks later after she had been on medication and then once a year after that. The medications were pretty cheap. I am looking at the same things with Perry at the moment. I don't know what the current costs are.

[Erny]

I wouldn't much bother with having thyroid tests conducted out here (ie Aussie). The tests are not full blood panel tests and the analysis of the results leave a bit to be desired, IMO.

I sent my boy's bloods for testing and analysis by Dr Jean Dodds in the USA. The Vet out here, of course, drew the blood, and I organised the necessary paperwork (with the guidance of Dr Jean Dodds and the info on her website) and arranged for them to be sent to her by international courier. There's a bit more fiddling around (due to the paperwork and courier) but I think it is worth it to know that the results are more likely to be accurate. From memory, the cost to me in Aussie dollars was something like $211.00. $111.00 of that was the international courier fee. There was also the local Vet's fee for drawing bloods.

What it would work out for you would depend on the USA/AUS exchange rate at the time. It's fairly good at the moment.

I remember comparing the costs to me at the time, to the costs to someone else who had their dog tested locally. I think it worked out about $50.00 cheaper to have them done in Oz.

It took one week from the drawing of the blood to receiving the test results. I think the average turn around is 7 - 10 days, which is pretty fast considering that a few of those days are taken up by the courier service delivery. If you go down this route, plan to have the bloods drawn on a Monday (equivalent to USA's Sunday) so that the weekend doesn't interrupt things.

Here's a link to get you started, if you're interested.

Welcome to Hemolife

Edited April 17, 2010 by Erny

[zayda_asher]

I wouldn't much bother with having thyroid tests conducted out here (ie Aussie). The tests are not full blood panel tests and the analysis of the results leave a bit to be desired, IMO.

You can have a full panel done here, you just have to request it...

[Staranais]

I wouldn't much bother with having thyroid tests conducted out here (ie Aussie). The tests are not full blood panel tests and the analysis of the results leave a bit to be desired, IMO.

You can have a full panel done here, you just have to request it...

Can you really? We can't in NZ (I think it's the free T4 we can't do, possibly also the autoantibody titres).

[Erny]

I wouldn't much bother with having thyroid tests conducted out here (ie Aussie). The tests are not full blood panel tests and the analysis of the results leave a bit to be desired, IMO.

You can have a full panel done here, you just have to request it...

ZA - unless it has changed over the last few years, I spoke to a couple of the laboratories (one referred me back to Gribbles) and they told me they do not have the facilities to check for the full blood panel tests as are done in the USA. The fellow I spoke to also informed me that it was unlikely to ever change due to costs -vs- demand (dog population in Australia insufficient by comparison to USA).

What do you consider to be the "full blood panel test" ?

Edited April 18, 2010 by Erny

[zayda_asher]

I was told I could get a full panel done here, if I wanted, by a health professional (I asked specifically)... Maybe we can in WA, I know we can get titers done here that you guys in the east have to send away for, so some labs here at least seem to do a little more

ETA: I see Dr Dodds has new testing as of 09, we wouldn't have that.

Edited April 18, 2010 by zayda_asher

[zayda_asher]

Can you really? We can't in NZ (I think it's the free T4 we can't do, possibly also the autoantibody titres).

I was told we could do the free T4

Edited April 18, 2010 by zayda_asher

[Staranais]

Can you really? We can't in NZ (I think it's the free T4 we can't do, possibly also the autoantibody titres).

I was told we could do the free T4

Oh that's pretty cool. We still can't do it here yet.

[zayda_asher]

Its weird... we always think of WA as "backwards", but it seems we are forward in some things!

[Erny]

I was told we could do the free T4

My understanding is that a full blood panel test comprises of six analytes :

TT4, FT4, TT3, FT3, T4aa, T3aa, TSH.

I won't pretend to understand the science of all the testing but I have read that "a TT4 assay may fail to detect thyroiditis, especially in its early stages". Also, the TSH test might not detect thyroiditis until 50 - 70% of the thyroid tissue has been destroyed.

Apparently an "elevated serum cholesterol" is another good indicator of thyroid disease. I have notes from when I did a bit of study on hypothyroidism affecting behaviour in dogs and although the "elevated serum cholesterol" might be the result of other things, apparently hypothyroidism is the most common cause.

[Staranais]

I was told we could do the free T4

My understanding is that a full blood panel test comprises of six analytes :

TT4, FT4, TT3, FT3, T4aa, T3aa, TSH.

I won't pretend to understand the science of all the testing but I have read that "a TT4 assay may fail to detect thyroiditis, especially in its early stages". Also, the TSH test might not detect thyroiditis until 50 - 70% of the thyroid tissue has been destroyed.

Apparently an "elevated serum cholesterol" is another good indicator of thyroid disease. I have notes from when I did a bit of study on hypothyroidism affecting behaviour in dogs and although the "elevated serum cholesterol" might be the result of other things, apparently hypothyroidism is the most common cause.

As I understand it, free T4 is also much less likely to give you a false positive than total T4 is. Your total T4 is often elevated in non-thyroid illnesses, so a low TT4 isn't a very good indicator of a malfunctioning thyroid.

[Erny]

As I understand it, free T4 is also much less likely to give you a false positive than total T4 is. Your total T4 is often elevated in non-thyroid illnesses, so a low TT4 isn't a very good indicator of a malfunctioning thyroid.

Not pretending to understand any of this and I can tell that I've copied it word for word, so it's not my head that knows this stuff, but from my 'notes' folder :

"Total serum T4 levels are compensated until there has been significant destruction of thyroid tissue. As free (unbound) T4 drops, the hypothalamus releases TRH, which stimulates pituitary secretion of TSH, with the remaining thyroid tissue increasing its T4 production. As the disease progresses, T3 levels are maintained as more T4 is converted to the active form of the hormone (T3). Total T4 (TT4) and free T4 (FT4) levels are artificially elevated by T4 autoantibodies (T4aa), while T3 autoantibodies (T3aa) depress total T3 (TT3) and elevate free T3 (FT3)."

This is where and why the TT4 might not pick up (especially) early stage thyroiditis.

But you probably know all this already . (And, what's more, you probably understand it too! :D)

Edited April 18, 2010 by Erny

[Rappie]

Total T4 is used as a screening test.

Free T4 by equilibrium dialysis is considered the 'gold standard' for measuring the T4 level as it is not affected by thyroglobulin antibodies.

If a low T4 if detected, then a TSH level is also run to see whether the low level is due to reduced output or whether the T4 is affected by non-thyroidal illness. Testing the T3 level is rarely of clinical significance.

I'm not sure of the value of testing for antibodies, except for in a breeding programs or in cases where a patient appears to have hypothyroidism but the other tests do not support it. If they are elevated, then a dog may be prone to progress to hypothyroidism - however hypothyroidism is a clinical syndrome so treatment is not indicated unless you have clinical signs of the disease AND supporting laboratory evidence. The antibody test may have predictive value but they do not dictate whether treatment is appropriate.

Edited April 18, 2010 by Rappie

[rajacadoo]

I wouldn't much bother with having thyroid tests conducted out here (ie Aussie). The tests are not full blood panel tests and the analysis of the results leave a bit to be desired, IMO.

You can have a full panel done here, you just have to request it...

About 6 months ago, I was looking into all this for one of my dogs...

I did the looking around and the ringing around, and I stopped the process when the finances got to close to $1000, for the same tests that Jean Dodds does. I finally got one company to tell me that the reason the costs were so high, was the lack of interest in getting the thyroid panels done, and they were trying to discourage it... Go figure. I really dont want someone that disinterested in my dogs health results, to do it actually :D . So that is where I sent my bloods too, Dr Jean Dodds. Not only was it sooooo much cheaper, I also liked the idea that my dogs thyroid panel was being assessed by someone who specialises in Thyroid diseases too :D Also she is VERY approachable as well. I have emailed her about 8-10 times, always with a prompt reply .

Ernie can I just correct you, and say that you dont need to get a courier to transport the bloods to Jean any more. If you follow her guidelines on her website, so long as you do everything 'to the t', there is no issue. I have sent 2 lots of bloods to her, over the last 6 months, both without the International courier. I sent the bloods myself at the PO . Much easier and MUCH cheaper !!!

[Erny]

Ernie can I just correct you, and say that you dont need to get a courier to transport the bloods to Jean any more. If you follow her guidelines on her website, so long as you do everything 'to the t', there is no issue. I have sent 2 lots of bloods to her, over the last 6 months, both without the International courier. I sent the bloods myself at the PO :D . Much easier and MUCH cheaper !!!

Thank you - I'll check up on her latest info. It would be great if the International Courier isn't necessary. But I presume you would still need to declare to Customs?

ETA: The other thing that I like with Dr Jean Dodds testing is their analysis base. They take into account not only whether the dog is small, medium or large, but also what breed it is and what age the dog is. Out here I believe the analysis is simply based on small, medium or large dog.

Edited April 18, 2010 by Erny

[zayda_asher]

Also she is VERY approachable as well. I have emailed her about 8-10 times, always with a prompt reply :D .

Yes, she is, I've spoken to her before on the subject of allergies and vaccinations. Very helpful and knowledgeable person

We didn't go any further with finding out about thyroid testing here, as it wasn't really appropriate in our case in the end, so just got the "yes, you can" but not into how much it might cost etc.

[stormie]

Total T4 is used as a screening test.

Free T4 by equilibrium dialysis is considered the 'gold standard' for measuring the T4 level as it is not affected by thyroglobulin antibodies.

If a low T4 if detected, then a TSH level is also run to see whether the low level is due to reduced output or whether the T4 is affected by non-thyroidal illness. Testing the T3 level is rarely of clinical significance.

I'm not sure of the value of testing for antibodies, except for in a breeding programs or in cases where a patient appears to have hypothyroidism but the other tests do not support it. If they are elevated, then a dog may be prone to progress to hypothyroidism - however hypothyroidism is a clinical syndrome so treatment is not indicated unless you have clinical signs of the disease AND supporting laboratory evidence. The antibody test may have predictive value but they do not dictate whether treatment is appropriate.

This is what I don't understand, with the whole sending blood to America. If they dog is still producing the 'normal' levels of T4, then you won't see clinical signs, right? The clinical signs we see from Hypothyroidism occur when the T4 drops low enough. So if your dog has skin condition and your 'standard' test comes back with normal levels, then it's unlikely to be a thyroid issue causing the problem. Even if the thyroid has been destroyed to 50% due to autoimmune problems, if its still producing normal levels of T4 then you won't see clinical signs.

Like Rappie, I see the importance of it for screening breeding dogs, but I don't see the relevance for testing every dog with a skin issue.

[Rappie]

This is what I don't understand, with the whole sending blood to America. If they dog is still producing the 'normal' levels of T4, then you won't see clinical signs, right? The clinical signs we see from Hypothyroidism occur when the T4 drops low enough. So if your dog has skin condition and your 'standard' test comes back with normal levels, then it's unlikely to be a thyroid issue causing the problem. Even if the thyroid has been destroyed to 50% due to autoimmune problems, if its still producing normal levels of T4 then you won't see clinical signs.

Like Rappie, I see the importance of it for screening breeding dogs, but I don't see the relevance for testing every dog with a skin issue.

If skin disease is severe enough to cause chronic stress and cortisol release, that could also push the T4 down.

I gather (and this is from general reading, not direct from source) that Dr Dodds obtains at FT4 level by a process that is not equilibrium dialysis. It is also my understanding that a treatment trial with thyroxine is frequently recommended by Dr Dodds when some of the thyroid levels are towards the low end of normal, even when all of the values are within the normal ranges specified by her own laboratory. These recommendations to treat are also (as I understand) made without ever having laid eyes, if not hands on a patient, which are the very basic requirements for having a valid veterinarian - client - patient relationship. The other issue that you may find is that the testing and treatment recommendations are not consistent with the current guidelines from other endocrinologists and this can certainly make vets uncomfortable with the process.

[stormie]

What I mean Rappie, is that if a dog has skin problems DUE to a thyroid problem, it is because the level of T4 being produced is too low, hence why you're seeing clinical symptoms. So if a dog comes in with bad skin and you do the standard aussie test and all are normal, it's very unlikely then that the cause of the bad skin could still be the thyroid?