Antibodies vary wildly, even intraday, which is why the result is considered positive or negative...raw number don't mean a lot. That being said, the NM doctor was right (in his test, your TPOab was significantly elevated), and your endo was right (in his test, TPOab was only marginally elevated).
Were they both working from the same U/S report?
NM doctor said you have autoimmune thyroid disease with "latent" hypothyroidism, endo said your thyroid function was normal. "Normal" here translates to "within reference range", which is not always good enough.
In both tests, your FT4 was low in the range...well below midrange, which is where many have to be for symptom relief. FT3 is very low in both cases. Unfortunately, TSH is in range on both tests, even the currently recommended range of AACE (0.3-3.0).
What are your symptoms? Does either want to treat you?
They both did an ultrasound themselves - their evaluation wasnt based on a report that they saw.
I dont really have any symptoms. I only went to see a doctor in the first place because I was at ENT doctor and he said my throat looks enlarged, which I dont really see..... NM doctor who the ENT suggested also said it looks enlarged. Endocrinologist says throat looks normal and not enlarged at all.
If I go down symptoms list, I guess I am tired (but I have 3 kids under age 4.5! and work full time) and I have gotten sick a lot since december (increased infections in winter months with 3 kids in pre-school is also pretty normal though)..... but other than that, nothing,
NM doctor wanted to put me on hormones. Endocrinologist said it isnt necessary since everything from his labwork and the ultrasound that he did was all normal.
A POSSIBLE explanation about the conflicting U/S diagnoses is the respective antibody levels at the time of each U/S. When antibodies are more active, they can cause swelling of the thyroid, when they die down, the swelling goes down. Enlargement can come and go, and it's possible for the thyroid to be quite enlarged before you can see it in the mirror.
Three kids under the age of 4.5 (better you than me!) and a full time job can do that to you. We have to be careful to ask the question as "Do you have unexplained tiredness?". The same for the infections...kids are little petri dishes of microbes.
I certainly think you should keep an eye on your thyroid levels and antibody levels. It's quite possible that you're in the early stages of Hashi's, but it can take antibodies years or even decades to cause enough damage to cause symptoms. There are two schools of thought (probably represented by your two doctors) on when to start treatment. Some think treatment should start sooner, rather than later, thus avoiding the unpleasnatness of going hypo and having to recover from that. Others think that until symptoms appear and/or FT3 and FT4 go out of range, the situation can just be monitored.
Only you know how you feel and how you want to proceed. Given that a good part of medicine is opinion and interpretation, I think both your doctors have made reasonable diagnoses. Take a really hard look at your symptoms and see if you think thyroid meds coud benefit. If you don't, just keep testing and be alert for any symptoms that might arise. You're in a very "gray" area.
My thyroid antibody results states normal <6IU or <60IU and my results (from two different labs) 47IU and 470U. So the conclusion:
IU (international units) x 10 = U (units).
Right then so what's up with 35IU? 35IU x 10 = 350U. 350U is normal? Ye..NO. lol
I means normal <6IU (international units) or <60U (units). One little I can make all the difference eh?
"In order to remove the possibility of having the letter "I" confused with the digit "1", some hospitals have it as a stated policy to omit the "I", that is, to only use U or E when talking and writing about dosages, while other hospitals require the word "Units" to be written out entirely."
I think U and IU are the same thing in this case. From what I've been reading lately, antibody ranges vary considerably lab to lab and are often "arbitrarily" set.
Regardless, the first TPOab is 4 times the upper limit of stated range, and the second is barely above range, so I think the two are an apples to apples comparison.
A pathologist from Sullivan Nicolaides Pathology, one of the two labs here in Qld, said the thyroid antibody testing they use (measured in international units) is different to the thyroid antibody testing (measured in units) at QML pathology and that you could not compare the two thyroid antibody lab results. My conversion formula looks in keeping with my results ha! but yeah just my conclusion. Why can't all labs be the same? *sigh* :)
And why were we (U.S.) never able to convert to the metric system??? I guess we shouldn't be too surprised at how long it's taking doctors and labs to revise their TSH ranges! The metric conversion has been all but abandoned.
At any rate, the first TPOab result is 199 with a range of <50, so the result is clearly almost 4 times the upper limit of the range. The second result is 36.7 with a range of <35. This is only marginally above the upper limit of the range. I think both results are in IU, the first using the abbreviation criteria I noted above.
The second doctor also interpreted the results as "only discreetly elevated", which is consistent with both tests being expressed in the same units. Even if the pathologist is right, if we assume that the second result would be 367 in U, then we also have to assume that the range would be <350 since both result and range would have to be converted to U instead of IU. No?
I get what you mean if you could indeed convert IU to U. Labs need a good kick you know where. :)
to be clear, regarding anti-TPO the first lab results says:
50 U/ml positive.
The second lab/doctors results says only
< 35.0 IU/ml normal
Therefore I assumed the doctors are using a "similar" unit of metric, and that there is not a factor of 10 here between them.
I was just suprised that the Anti-TPO values can change so much in just 2 weeks. The first doctor visit was on March 1st and the second doctor visit was on March 15th. Have you all experienced that the TPO values varry so much in such a short periold of time.
Antibody counts can vary wildly even intraday. This is another reason why raw numbers are pretty insignificant. The result is either positive or negative.
I agree with you. I don't think there's a factor of 10 between them.