Medication dose

[Teenidol]

I have been taking levothyroxine for a number of years. I have been on 150mcg for a few years now and having regular blood tests to check I am taking the correct dose. After my most recent test I was called back to have another blood test a few weeks later. The nurse said my test had come back low . My second test was low again and the doctor I saw said this meant they were over treating my under active thyroid! He has subsequently reduced my dose of levothyroxine.

I am confused - surely if my thyroid test is coming back low my medication would be increased?! The levothyroxine is meant to supplement what my thyroid doesn't produce surely?!

[shaws Administrator]

I assume that what the doctor means with:-

"My second test was low again and the doctor I saw said this meant they were over treating my under active thyroid"

as it would appear that it is your TSH whch is very low. Therefore, with people who don't really know very much about the function of the thyroid gland, ASSUME that we're on too high a dose and verging on hypERthyroidism and therefore reduce it.

Do you always get the very earliest appointment? Fasting? and do you allow a 24 hour gap between your last dose and test?

If not, your results will be skewed.

[SeasideSusie Remembering]

Teenidol

I am confused - surely if my thyroid test is coming back low my medication would be increased?!

I assume that all they've tested is TSH (thyroid stimulating hormone). This is not a thyroid hormone but a signal from the pituitary to tell the thyroid to make hormone if it detects there's not enough. If the pituitary knows there is enough thyroid hormone then it doesn't send the signal TSH so it remains low.

For a full thyroid picture we need to test:

TSH

FT4

FT3

but many surgeries only do TSH, some also include FT4, occasionally FT3 is included if TSH is suppressed. The lab ultimately makes the decision on whether or not FT3 is included.

So what you need to do is ask the receptionist for a print out of your results (our legal right here in the UK) then post that result on the forum, with the reference range which will be on the print out, and members will comment.

If it appears that your GP wants to reduce your Levo purely due to your TSH result, then if you feel well on your current dose ask for FT4 and FT3 to be tested. If FT3 is over range then that suggests overmedication, if it is within range you are not overmedicated. In your position I would refuse any reduction until further testing has been done to prove overmedication or otherwise.

Also, as Shaws has mentioned, we need to make sure we do our thyroid tests correctly. Always advised here is:

* Book the first appointment of the morning, or with private tests at home no later than 9am. This is because TSH is highest early morning and lowers throughout the day. If we are looking for a diagnosis of hypothyroidism, or looking for an increase in dose or to avoid a reduction then we need TSH to be as high as possible.

* Fast overnight - have your evening meal/supper as normal the night before but delay breakfast on the day of the test and drink water only until after the blood draw. Eating may lower TSH, caffeine containing drinks affect TSH.

* If taking thyroid hormone replacement, last dose of Levo should be 24 hours before blood draw, if taking NDT or T3 then last dose should be 8-12 hours before blood draw. Adjust timing the day before if necessary. This avoids measuring hormone levels at their peak after ingestion of hormone replacement. Take your thyroid meds after the blood draw. Taking your dose too close to the blood draw will give false high results, leaving any longer gap will give false low results.

* If you take Biotin or a B Complex containing Biotin (B7), leave this off for 7 days before any blood test. This is because if Biotin is used in the testing procedure it can give false results (both Medichecks and Blue Horizon advise to leave Biotin/B Complex off).

These are patient to patient tips which we don't discuss with doctors or phlebotomists.

[SlowDragon Administrator]

Just testing TSH is completely inadequate

On correct dose of Levothyroxine TSH is frequently low

Before agreeing to any dose reduction you need FULL Thyroid and vitamin testing

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

Vitamin levels also drop as we age, especially B12

Ask GP to test vitamin levels

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Is this how you do your tests?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins

thyroiduk.org.uk/tuk/testin...

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

How much does GP want to reduce dose by?

Many people find Levothyroxine brands are not interchangeable.

Once you find a brand that suits you, best to make sure to only get that one at each prescription. Watch out for brand change when dose is increased or at repeat prescription.

Many patients do NOT get on well with Teva brand of Levothyroxine. Though it is the only one for lactose intolerant patients. Teva is the only brand that makes 75mcg tablet.