Blood test question

[Jelley93]

So on Tuesday I will have a thyroid function blood test from the DR. Ive been a bit unwell since 22/04/2021. Main issue is a feeling of being unbalanced or dizzy. Ive been on 100mcg since 2018 with no problems to speak of. So when I have the blood test. How long does it take for the results to come back. If they find the readings are either too low or too high. How long would a levo increase or decrease take to kick in to my system. Im currently on sick, Im guessing ill need a longer certificate for sickness.

[SlowDragon Administrator]

Presumably you have Hashimoto’s as hypothyroidism started after glandular fever

You are legally entitled to printed copies of your blood test results and ranges.

The best way to get access to current and historic blood test results is to register for online access to your medical record and blood test results

UK GP practices are supposed to offer everyone online access for blood test results. Ring and ask if this is available and apply to do so if possible, if it is you may need "enhanced access" to see blood results.

Link re access

healthunlocked.com/thyroidu...

In reality many GP surgeries do not have blood test results online yet

Alternatively ring receptionist and request printed copies of results. Allow couple of days and then go and pick up.

Important to see exactly what has been tested and equally important what hasn’t been tested yet

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested.

Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies

Far too often only TSH is tested, even if GP requests more

[Jelley93 in reply to SlowDragon]

Coded entry - Serum free T4 level (XaERr) 18 pmol/L [9 - 25]Coded entry - Serum TSH level (XaELV) 5.2 miu/L [0.3 - 5]

Coded entry - Thyroid function test (X77Wg)

Found these on my nhs record. Last blood test September 2020

[SlowDragon Administrator in reply to Jelley93]

So your GP should have increased levothyroxine by 25mcg immediately after these results came in

Looks likely you took levothyroxine BEFORE blood test?

ALWAYS test as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours BEFORE TEST

The aim of levothyroxine is to increase dose upwards in 25mcg steps until TSH is ALWAYS under 2

When adequately treated, TSH will often be well below one.

Most important results are ALWAYS Ft3 followed by Ft4. When adequately treated Ft4 is usually in top third of range and Ft3 at least 60% through range (regardless of how low TSH is)

Extremely important to have optimal vitamin levels too as this helps reduce symptoms and improve how levothyroxine works

ALWAYS get copies of results after any blood test

Keep good records yourself

The only person who can manage your hypothyroidism well....is you

[Jelley93 in reply to SlowDragon]

Nope like I say been lingering on 100mcg for 3 years. I'm guessing the TSH level is too high. I've heard it's good below 3.

[SlowDragon Administrator in reply to Jelley93]

Link showing TSH should be under 2 as an absolute maximum when on levothyroxine

gponline.com/endocrinology-...

Replacement therapy with levothyroxine should be initiated in all patients to achieve a TSH level of 0.5-2.0pmol/L.

New NHS England Liothyronine guidelines July 2019 clearly state on page 13 that TSH should be between 0.4-1.5 when OPTIMALLY treated with just Levothyroxine

Note that it says test should be in morning BEFORE taking levothyroxine

Also to test vitamin D, folate, B12 and ferritin

sps.nhs.uk/wp-content/uploa...

Aim is to bring a TSH under 2.5

UK guidance suggests aiming for a TSH of 0.5–2.5

gp-update.co.uk/SM4/Mutable...

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance.

But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

(That’s Ft3 at 58% minimum through range)

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor



please email Dionne at

[e-mail]

[SlowDragon Administrator]

Assuming you need dose increase in levothyroxine, it typically takes 4-6 weeks to start to see improvements

Improving Low vitamin levels can significantly improve symptoms too

Which brand of levothyroxine are you currently taking

Has it changed recently

Have you had Covid?

[Jelley93 in reply to SlowDragon]

Mercury pharma. Always been on this one

[SlowDragon Administrator in reply to Jelley93]

That’s easy then as Mercury Pharma make 25mcg, 50mcg and 100mcg tablets

Come back with new post once you get results

[Jelley93 in reply to SlowDragon]

Ok will do cheers

[SlowDragon Administrator]

So you need 25mcg dose increase in levothyroxine

Bloods should be retested 6-8 weeks after dose increase. May need further increase after next test

Or may need to improve low vitamin levels

Ask GP to test vitamin D, folate, ferritin and B12 now

Levothyroxine is an extremely fussy hormone and should always be taken on an empty stomach and then nothing apart from water for at least an hour after

Many people take Levothyroxine soon after waking, but it may be more convenient and perhaps more effective taken at bedtime

verywellhealth.com/best-tim...

No other medication or supplements at same as Levothyroxine, leave at least 2 hour gap.

Some like iron, calcium, magnesium, omeprazole or vitamin D should be four hours away

(Time gap doesn't apply to Vitamin D mouth spray)

If you normally take levothyroxine at bedtime/in night ...adjust timings as follows prior to blood test

If testing Monday morning, delay Saturday evening dose levothyroxine until Sunday morning. Delay Sunday evening dose levothyroxine until after blood test on Monday morning. Take Monday evening dose levothyroxine as per normal

REMEMBER.....very important....stop taking any supplements that contain biotin a week before ALL BLOOD TESTS as biotin can falsely affect test results - eg vitamin B complex