Minimum time on levothyroxine dose before testing levels

[Curious123]

What is the minimum time someone should be on a dose of levothyroxine before checking thyroid levels? NHS GP suggests 8 weeks. I had a TSH of 48.2 and FT4 3.9 and started levothyroxine 50mcg daily. I saw a private Endo who said to titrate up to 75mcg for 1 week and then go to 100mcg. I had been on 100mcg for approximately 2 weeks when I had a re-test on NHS and TSH was 7.23 (0.27-4.2), FT4 17.1 (10.8-25.5). GP suggested going to 50mcg/75mcg alternate days (not aware I had increased to 100mcg). Just wondering what to do. I won’t be seeing the private endocrinologist again as it was £330 for the appointment and my private health doesn’t cover that specialist. NHS appointment referral was made Aug23 but no appointment until Apr24.

[jimh111]

About four weeks is a minimum time for the first blood test, six or eight weeks gives a more precise measurement but the first test will give a ball park figure that will give an idea whether you need an increase or reduction.

I would tell your GP you are on 100 mcg otherwise they can't help you and it's not fair on them. You will probably need an increase but I would stay on 100 mcg for at least four weeks before doing another blood test.

[Regenallotment Ambassador]

Patient info leaflet says 4 weeks

My GP and Roseway prescriber say 12

This forum often says 6-8

Personal experience when titrating up, 8 suited me. Once up to 100mcg I need 12 to really see what’s going on.

My usual pattern for symptoms while titrating up, Week 1 & 2 feel amazing. Week 3&4 a dip that plateaus them rises slowly through 5,6,7 improved by 8.

Worth working on vitamins, diet etc in parallel. Sorting D Bs Ferritin and folate, gluten and dairy free did as much of not more for me than just the Levo. 🌱

[Curious123 in reply to Regenallotment]

Yeah, I already work on vitamins and minerals due to other health conditions. Thank you for your personal experience.

[SlowDragon Administrator]

I would tell GP why and when you increased dose to 100mcg

Retest 6-8 weeks after any change in dose or brand of levothyroxine

Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test and last dose levothyroxine 24 hours before test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

If not tested already

Request testing of vitamin D, folate, ferritin and B12 at next test

Plus thyroid antibodies for autoimmune thyroid disease

What vitamin supplements are you taking

[Curious123 in reply to SlowDragon]

Thanks. I had followed that approach for the test. Separately I had privately tested antibodies as I knew nothing would happen on that front at least not before an NHS appointment came through. Vitamins are a bit limited at the moment due to current life circumstances but will be working on them shortly. My VitD is 74 but I usually target 100 with that.

[SlowDragon Administrator in reply to Curious123]

Looking at previous posts

You test positive just for TSI antibodies (Graves disease)

and also high TG antibodies

What about TPO antibodies?

[Curious123 in reply to SlowDragon]

TPO are still negative. Medichecks test was:

TgAB 447 (0-115) and TPO 19.8 (0-34)

That was late September a month on levothyroxine. Antibodies haven’t been tested since.

[Ellie-Louise]

The doctor told me to re-test after 6-8 weeks. I told her I would make it 8. Actually I think that would take me to Christmas so I might have to re-think.

A few weeks ago the receptionist told me I would need to make an appointment a month before I needed it. When she rang me about my results last week I asked the doctor if I could have a steroid injection in my knee, she said she would put me on the list. That is two lists I’m on now, one is from last December!

These new rules are so awkward and a face to face with a doctor seems rare. They would rather do phone calls now and they call it progress! It seems to me that the whole world is turning backwards.

I needed a rant, sorry about that.

[Sparklingsunshine in reply to Ellie-Louise]

My old GP who I'd had for years retired from general practice after Covid, much to my regret. She's still involved in training new GP's but said her experience of phoning patients all day made her feel like a call centre worker, not a doctor.

She very much missed the human interaction of actually seeing patients f2f. It may mean more patients get treated in a day under this new system but I worry about serious issues being missed. It may suit GP's but not sure its the same for us patients.

[Curious123 in reply to Ellie-Louise]

Totally understand. I just received a text they had reviewed the blood test results and were changing the dosage and sending the script to the pharmacy. It was all quite efficiently but didn’t give the opportunity to discuss any symptoms or the endocrinologist guidance. We now can’t book appointments but rather have to fill in an online form and then they reply and call to make an appointment so everything is triaged. It was efficient when I had an issue to deal with a few weeks ago but is challenging when you need a face to face and don’t necessarily want everything to discuss down in writing.

[Ellie-Louise]

A good few months ago I was told to fill the form in, it was when I got to the part where they needed a screenshot of my driving licence that I logged off and rang them. The woman who answered told me how to skip right to the box where I could write down what was wrong. I haven’t bothered with that online box rubbish again.

[SilverAvocado]

I tend to use 6 weeks as my rule of thumb for how long to stay on a dose before having a blood test. I was always made to wait double that by my doctor. All rules of thumb are compromises, because in fact the experience on a given dose continues developing for months, and some symptoms take years to resolve.

My personal experience is a bit more chaotic than others have mentioned. I find that shortly after a dose change I can feel almost any kind of symptom. That has included feeling either more overdosed or underdosed than I actually am, appearance of a brand new symptom, or sometimes feeling great. Around the four week point things settle down a bit, bit I still feel it can be a bit up and down for several weeks after that.

I think others are right that it makes a bit of a difference what you expect to find out from a test how important it is to wait. Once you are close to your ideal dose, you will want to wait as long as you can manage, because you care about very accurate results and not overshooting your sweet spot.

Two weeks does seem pretty short, though. You had been on 100mcg for two weeks, and three weeks prior you'd been on 50mcg? I don't think you can conclude too much from these results. TSH in particular is on the slower side to move, and these are a much more extreme set of changes than I have any experience with.

If you did want to interpret these blood tests, the kind of numbers you are hoping for is a TSH close to 1, many people will need it lower than that, and a freeT4 at the top of the range. Yours is miles away from that. It is quite possible you will need a few more increases, as 100mcg is on the low side for a dose of Levothyroxine. Symptoms are more important than numbers, so the ultimate goal is to resolve symptoms. If you are lucky, as freeT4 approaches the top of the range you will feel much better.

Best practice for an adjustment in dose is 25mcg per day. Your GP's suggestion of increasing by 25mcg on alternate days make no sense at all, as the results they have seen suggest you are still very hypothyroid.

What you do next also depends on where you are with your prescription. Will you have an ongoing prescription for 100mcg from your private provider, or are you dependent on the GP? If you could go back in time I would have suggested you stall your GP blood tests until they linked up with when you were ready for it based on your dose adjustments. But it is still something to bear in mind for the future.

It seems like you are in the situation of trying to manage your GP and specialists as much as you can. What you need in the near future is a repeat blood test once you are settled on 100mcg, and then a dose adjustment if necessary. It is very likely you will need an increase, and will likely need one or more retests then be increase after that.

It also depends how you are feeling how urgent all this is. Your first blood test and adjustment is pretty essential. But you may be starting to feel some improvement by then, and if you're lucky getting close to the dose that will help you a lot.

The first option is probably to make yourself a GP appointment after 6-8 weeks and go in and beg them to help you. I would suggest being transparent with them about seeing a private doctor, as you are really only at the start of the process of trying to get better and it is your right to go private. You haven't done anything nefarious. I find GPs tend to react quite positively to talk of having seen a private doctor. I think they hear it all the time. Although if your private doctor didn't write them a letter with the recommended dose they might not give your word as much weight.

If you can't get your retest through the GP, it is much more cost effective to order mail order finger prick blood tests than to see a private doctor. You will then have to learn to read the thyroid panel yourself. This forum is a great place to learn about the tests, I recommend reading regularly, looking at other people's posts and seeing what members advise.

[Curious123 in reply to SilverAvocado]

Thanks. I’ve been diagnosed with postpartum thyroiditis so the body is adjusting back to the immune system change of pregnancy and postpartum. So I was hyperthyroid and in less than 2 months flipped from TSH <0.01 to TSH 48.2. Perhaps that is why my swings have been quick and extreme, versus Hashimotos or Graves pulling mainly in one direction?

[Jaydee1507 Administrator in reply to Curious123]

Hashimoto's can often have a hyper phase in the early stages then go hypo. You may well have Hashimoto's but time will tell.