What does this mean? Comparing older tests

[lily82]

Hi

I found some old thyroid tests I had done back in 2009. It was something my GP did (I think it was because I was fatigued) and I only found the tests results recently as I asked for my records. (I'm now 35, female)

Back in 2009 my results were (marked as normal, no action)

Free T4 16.5 pmol/l (9.8 - 23.1)

TSH 0.73 mu/L (0.35- 5.50)

Recently my results were

Free T4 level 10.9 pmol/L (9.0-19.1)

TSH 3.41 mu/L (0.30- 4.40)

Thanks!

[Clutter]

Lily82,

'Normal' means that results are within the lab ref range (the figures in brackets after the results).

Your 2009 results were unequivocally euthyroid (normal) with low-normal TSH and slightly below mid range FT4.

Your recent results are also normal as they are still within range but TSH >2.0 indicates the thyroid is beginning to struggle. TSH has risen because FT4 has dropped. You have been advised to ask your GP or endo consider secondary hypothyroidism because of your brain injury and other low hormones.

[lily82 in reply to Clutter]

Ah thanks.

I just wasn't sure why certain levels would change and what they meant. In terms of which levels indicate what. (I.e what does it mean if T4 goes up or down etc).

[Clutter in reply to lily82]

Lily82,

TSH = thyroid stimulating hormone which is a pituitary hormone. TSH rises when T4 and T3 thyroid hormones are low, and TSH falls when T4 and T3 rise.

You need reasonable levels of T4 to convert sufficient T3. If T4 is low invariably T3 will be low too, and it is low T3 which causes hypothyroid symptoms.

Although your T4 is within range you can see how much lower it is now than in 2009 and how your TSH has risen correspondingly. Normally one would expect TSH to continue rising to improve T4 but with a brain injury it is possible there is pituitary dysfunction and this may not happen and TSH may remain low although FT4 is dropping lower.

[lily82 in reply to Clutter]

Brilliant! Thanks so much for that explanation.

That's exactly what I wanted to know.

I'll take these old results with me to see the endocrinologist, for comparison.

[SlowDragon Administrator]

Do you have high thyroid antibodies? Essential to be tested. Plus vitamin D, folate, ferritin and B12

Low vitamins are common when hypo and low vitamins stop thyroid hormones working well

If low they may need supplementing

[lily82 in reply to SlowDragon]

Thanks. I didn't get anti bodies tested.

My ferritin was on the low side (probably due to frequent and heavy periods). Also my B12 was on the low side. Vitamin D was fine- I take supplements.

Since I had the initial tests back in 2009, my periods got more and more frequent. So could that have affected it?

At one point my B12 was so low they were considering injections as I was deficinent but levels have gone up, but still on the low-ish side.

I found that some symptoms improved after giving up gluten (digestion etc). Dunno if that's a coincidence. I idon't have Celiac disease, probably just an intolerance.