Vitamins & blood test

[Quinc]

Before a blood test we make sure there is a 24 hour window Levothyroxine free.

Does the same apply to Vit B12 & Vit D please might someone tell me? I have recently started taking both daily.

I need to be tested for these 2 vits (alongside the ferretin, folate & iron) as part of a full thyroid blood check as current medication regime really not working!

Thanks

[SlowDragon Administrator]

Stop vitamin D and B12 day before test

You would need to be off B12 4 months to get a pre supplement result…..so just stop day before

How much levothyroxine are you currently taking

What were most recent thyroid results

Always test thyroid levels early morning, ideally before 9am and last dose levothyroxine 24 hours before test

Do you always get same brand levothyroxine at each prescription

[Quinc in reply to SlowDragon]

Thanks, most helpful.I am on 25m per day, reduced from 50 as it seemed to be causing palpitations.

I know that this a very small dose but I really don’t get on with Levo too well. Still feeling awful some days. Covid seemed to make everything worse.

I am on Wockhardt. Always the same.

Last TSH March 2.55 ‘normal’

In Feb it was 4.55 ‘abnormal’

[SlowDragon Administrator in reply to Quinc]

Being UNDER medicated can cause palpitations …..or different brands can cause issues

Approx how old are you

Levothyroxine doesn’t top up failing thyroid it replaces it

So almost everyone needs to increase dose levothyroxine slowly upwards in 25mcg steps (or 12.5mcg if 25mcg is too much)

When did you reduce dose to 25mcg

You could try splitting the levothyroxine as 25mcg waking and 25mcg at bedtime

Perhaps initially increasing only by 12.5mcg …..waiting 6-8 weeks then retest before increasing to 50mcg every day (initially as split dose)

Last TSH March 2.55 ‘normal’

In Feb it was 4.55 ‘abnormal’

Do you mean March 2021

And Feb result 2022

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.

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...

Graph showing median TSH in healthy population is 1-1.5

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

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...

guidelines on dose levothyroxine by weight

Even if we frequently don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose

NICE guidelines on full replacement dose

nice.org.uk/guidance/ng145/...

1.3.6

Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.

Also here

cks.nice.org.uk/topics/hypo...

gp-update.co.uk/files/docs/...

Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.

For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.

For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).

If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.

BMJ also clear on dose required

bmj.com/content/368/bmj.m41

healthunlocked.com/thyroidu...

jamanetwork.com/journals/ja...

Guidelines are just that ....guidelines. Some people need more …….some need less

healthunlocked.com/thyroidu...

[Quinc in reply to SlowDragon]

Thanks Actually both tests this year.

I stopped taking it altogether (on doc’s advice) over last summer and started late autumn trying every other day … but not good so went to 25 each morning and stayed.

I am very late 60’s

I would dearly love to live without meds

[SlowDragon Administrator in reply to Quinc]

So you should START on 25mcg

But dose should still be increased SLOWLY upwards

Try small increase to 37.5mcg (cutting 25mcg tablet in half)

Retest after 6-8 weeks

Always test early morning and last dose levothyroxine 24 hours before test

Levothyroxine isn’t a medication….it’s replacement thyroid hormone, because your unable to make enough

Just like a diabetic needs insulin we need replacement thyroid hormones

You won’t feel well unless on high enough dose and all four vitamins are at GOOD levels

High cholesterol is strongly linked to being hypothyroid/under medicated

[Quinc in reply to SlowDragon]

Many thanks SlowDragon,Really good & interesting advice and I have possibly learnt more from you than my (assortment) of doctor calls/visits

[SlowDragon Administrator in reply to Quinc]

When you increase…….stick with Wockhardt….they only make 25mcg tablets….request GP increase prescription to 56 tablets a month

Then you can trial increasing dose without changing brand

Only changing one thing at a time is essential to make progress

So changing dose or change brand….but never both at same time

Levothyroxine is cheap as chips ……..unlike T3

Getting all four vitamins optimal can significantly improve symptoms and help tolerate increasing dose levothyroxine

[humanbean]

Low iron and/or ferritin (iron stores) can cause palpitations.

If you are getting an iron or ferritin test, and you take iron supplements in any form, you should stop taking iron for 5 - 7 days before the test, and don't eat an iron-heavy meal in the 24 hours before the blood draw.

The test also needs to be done having fasted for 12 hours before the blood draw, and do the blood draw by 9am. Drinking plain water is fine. Don't get dehydrated.

[SlowDragon Administrator]

Come back with new post once you get full iron panel test including ferritin results