new T4 reference ranges - anyone else heard of these?

[Buttercupsareyellow]

So a year ago my T4 was 11.9. Reference range at time was 12-22

Scroll forward one year and my T4 is 9.0 OK I think that is below reference range, but no- new guidance for reference range - apparently it is now 8-18!!!!!!!

Am I being paranoid or are we being gaslighted?

Anyone else had experience of this?

Should add TSH just slightly low (the usual snarky comment about considering reducing dose 🤦‍♀️ and T3 at absolute bottom of range. - Had wondered why I had put on nearly a stone in the last year and they are still recommending reducing dose 😡

nbt.nhs.uk/severn-pathology....

[greygoose]

Ranges change all the time. They are determined by the calibration of the machine used in the analysis. So, I expect the lab in question got a new machine. So, no, we are not being gaslighted. And that is why on here with convert results into percentages through the range, so that we can compare results that have different ranges.

FT4: 11.9 pmol/l (Range 12 - 22) -1.00%

FT4: 9 pmol/l (Range 8 - 18) 10.00%

So, your FT4 has gone up a little, which isn't surprising, levels can fluctuate, but it's still very very low. And if your FT3 is also at the bottom of the range then you are under-medicated, and that's why you've put on weight.

The question is: why is your TSH so low with such low Frees? What time of day was the blood draw for this test?

[Buttercupsareyellow in reply to greygoose]

Thanks for explaining. That would make sense re machine!

It is very odd as my TSH has been suppressed ever since I had thyoid fully removed and they finally got me on a decent dose of levothyroxine (back in 2008). T4 ran high for years on mono therapy, but still had hypo symptoms and weight gain. Have been on NDT for last 3.5 years. Feel generally much better, but still weight (which initially went down) has gone back up and T3 and T4 never go up, despite low TSH. Should add TSH not as low as used to be, now hovers at 0.09/0.1 (endo says happy once 0.1 due to NDT) always used to be 0.02-0.04 range. They were ok with this until I hit menopause then started freaking out (I think AF risks and osteoporosis risks increase allegedly after menopause which might explain their anxiety). I have always countered risks of diabetes, heart disease, high blood pressure etc increase if you start to gain too much weight - I am assessing risk and choose low TSH risks if it helps me maintain weight (if that makes sense) .

I always have a morning test before meds, empty stomach etc. As combined pill can understand T3 may be on lower side, but need 24 hours for the NDT and small dose of levothyroxine I take.

Next endo appointment not until May/June to review and write prescription (I get years supply at time of NDT) - always careful storing it as well so it doesn’t get too hot/cold or damp……

[SlowDragon Ambassador in reply to Buttercupsareyellow]

Please add Ft3 result and vitamin D, folate, ferritin and B12

[Buttercupsareyellow in reply to SlowDragon]

I don’t have those, but might be useful to have

[greygoose in reply to Buttercupsareyellow]

Even so, it does sound as if you need to increase your NDT - why not do that rather than take extra levo?

To hell with the TSH, it's totally irrelevant at that level and taking NDT. And it has nothing to do with hearts or bones. Your pituitary has stopped making it because it decided you didn't need it anymore, that's all.

[SmallBlueThing]

In my area area, the reference range for fT4 changed from 9.0~25.0 to 11.5~22.7 pmol/L and for TSH changed from 0.3~5.0 to 0.55~4.78 mIU/L, about a year ago. It takes weeks to book a blood test at my surgery, despite them saying important monitoring is required.

The reference range for adjusted calcium is now 2.12~2.51 mmol/L with a footnote that it was amended to account for the calibration difference in the assay. People with mild hypocalcaemia were already regularly fobbed off, with the superseded range of 2.2~2.6 mmol/L (GP saying she wasn't interested unless it was 1.9 mmol/L or lower). On the other hand, those with hypercalcaemia should be caught earlier.

[Agitator23]

My endocrinologist just ignores the different ranges and goes for the FT4 and FT3 read out only. He wanted my FT4 at 20 p/mol regardless of lab range.

All this fiddling with ranges, differences over time and lab location seem quite random. The 'science' behind machine calibration is opaque. I've mentioned this in other posts and comments.

What are the reasons behind all this inconsistency - and the changes that make it more difficult to be diagnosed with hypothyroidism? Just wondering...