Subclinical or Overt Hypothyroidism?

[yewotc23]

Hi guys, I've read that there's 'Subclinical Hypothyroidism:' - mild form of hypothyroidism where the only abnormal hormone level is an increased TSH. And 'Overt Hypothyroidism': clear hypothyroidism characterized by an increased TSH and a decreased T4 level

Was looking back at my very first thyroid results and wondering whether mine is sublicinal hypothyroidism or overt hypothyroidism?

The very first were:

Serum TSH - 11.9 [0.27 - 4.2]

Serum free T4 - 12 [12 - 22]

My T4 was the very bottom of the range, but in range so this means mine is sublicinal hypothyroidism?

[SlowDragon Ambassador]

You had overt hypothyroidism as TSH over 10

Starting levothyroxine - flow chart

gps.northcentrallondonccg.n...

Graph showing median TSH in healthy population is 1-1.5

web.archive.org/web/2004060...

[yewotc23 in reply to SlowDragon]

SlowDragon I've always wondered which I had, so thanks for the reply

[yewotc23 in reply to SlowDragon]

SlowDragon I've got my annual review at the doctors on 3rd April, i know you say early morning blood test is the best. 9:25am was the earliest I could get, will that be okay?

[SlowDragon Ambassador in reply to yewotc23]

Yes should be fine

Remember last dose Levo 24 hours before test

And stop any supplements that contain biotin 3-5 days before test

[tattybogle]

well technically , it's still 'sub clinical' whatever the TSH is , and if your fT4 was just 0.01 lower at 11.99 then technically it would be overt ... but bear in mind that it could very easily have been 11.99 or even a bit lower if tested just 45 minutes earlier or later on the same day .. fT4 is produced in multiple little peaks over the day , it's not a totally steady measurement all day ..... so it's all a bit academic in your case and it doesn't make any difference what label it's given.

and since your TSH is over 10 ....

(NHS recommend that TSH over 10 should be treated with levothyroxine even if no symptoms of hypothyroidism are present, and NHS endocrinologists when in doubt about an earlier diagnosis of hypothyroidism use 'history of TSH over 10' as proof of correct diagnosis of hypothyroidism / need for levo )

..... then 'overt' / 'subclinical' label should make no difference to your treatment going forwards . TSH over 10 gives you a clear diagnosis of hypothyroidism that the NHS agree needs treatment with levo. and whether your fT4 is just within range or just below , makes absolutely no difference to that.

it's just an arbitrary line that someone drew in the sand .... sub clinical and overt are not different diseases. people feel just as crap with fT4 at 12.01 as they do with 11.99

[tattybogle in reply to tattybogle]

oh , and another point about that 'arbitrary line in the sand ' .....the whole castle is 'build on sand' .

FT4 testing is not yet standardised across the UK ... different fT4 assays (test machines) will not give exactly the same result even from the same blood sample , if you happened to live 30 miles away meaning your sample was sent to a different hospital lab who had an assay machine made by someone else , then your ft4 result would be slightly different..... so this is another reason why the 'sub clinical' label is completely arbitrary.

for example , i recently had these results ~ taken just 45 minutes apart , one tested at GP , one sent privately to NHS hospital lab in Exeter... (so both NHS labs , and if i happened to live in Exeter my GP test would be processed by this lab)

GP ~TSH 2.65 [0.57 -3.6] fT4 15.7 [7.9 -14] ie. 128% through range

Exeter ~ TSH 2.9 [0.27 -4.2] fT4 22.1 [12-22] ie, 101% through range

as you can see ,FT4 testing in uk is far from standardised...it's an embarrassing mess.

[JoJoloveschocolate in reply to tattybogle]

This is what I don’t get about it all. My tsh was only 4.7 (just over range on 2 tests)at diagnosis and yet and my ft4 was only 12.3 (12-22).

I don’t understand why the tsh wasn’t higher.

They said I was subclinical even though I had horrendous symptoms and a previous diagnosis of CFS (sorry to interrupt the original poster’s question)

[FallingInReverse]

Per past posts you’ve been on Levo for 4 years already?

I like what tatty says - they are not different diseases, so it’s an interesting question to ask all these years later as if we all had continuous thyroid blood monitors early enough I bet we would all go through a sub-clinical phase.

But it’s not a different disease, you are just hypo and always were, the blood test was just a moment in time as your hypo progressed.

I think my point is that doctors use the sub-clinical label to delay treatment, using sub clinical as a synonym for asymptomatic. This is not true at all as lots of people with “in range” free ts are symptomatic and ranges are useless anyway, and the sub-clinical label has kept a lot of people dick longer than needed.

[yewotc23]

FallingInReverse Thanks. Yeah, been on Levo for 4 years. Just was confused with the subclinical and overt thing