Lab result question so confused

[Kokepelli]

My TPo was less than 1 (in range)
Tgab 8 (range <1)
Tsh 3.73 (in range)

I had taken 75 mcg of synthroid for about 10 days then stopped four days prior to lab.

My tsh has gone in and out of range to hypo for a couple of years.  I have multiple sclerosis, RA and lupus.  Does the out of range tgab mean I have Hashimoto?

[Barb135]

That's a strange reference range for the FT4, but your level is considerably lower than we'd, typically, recommend. Rule of thumb for Free T4 is mid range and yours is only at 37% of the range, so you have a ways to go to reach the target.  

It would have been good if the doctor would have ordered Free T3, as well, because Free T3 is the active hormone that's used by every cell in your body, while Free T4 is considered a "storage" hormone or "pro-hormone" that has to be converted to Free T3, prior to being used.

In view of the relatively low Free T4, I'd say you do have some thyroid damage going on and would most likely be diagnosed with Hashimoto's.  

Since you already have RA, MS and Lupus (all autoimmune), the likelihood of getting another (or more) autoimmunes is greater, since autoimmune conditions, often, tend to come in "clusters".

Unfortunately, TSH is affected by things, other than thyroid hormones, and can fluctuate by as much as 75% over the course, of a day.  It tends to be highest in the morning, so simply having blood tests done at different times of day could explain fluctuations.

It really wasn't necessary to stop the medication.  It takes 4-6 weeks for it to reach full potential and the endo would have been able to look at your labs and symptoms to see what was going on.  

When is your endo appointment?

[Barb135]

TgAb can also be slightly elevated when one has other autoimmune conditions, such as RA and MS, so no, your result doesn't necessarily mean Hashimoto's.  

Is TSH the test related to thyroid function you've had done?  What about Free T3 and Free T4?  Those are the actual thyroid hormones and are much more important than TSH.  

Why did you only take the synthroid for 10 days, then stop prior to the blood test?  

[Kokepelli]

My t4 free is 1.5 range 0.8-2.7.  I stopped taking it because it was given to me by my family practice doctor after seeing the few TSH fluctuations.  But once I got an endo referral, I thought I should see his opinion before continuing the medicine.