Thyroid UK
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Changing blood levels

Hi,My first lab results were TSH 4.37,FT3 4.9,FT4 14.6. Based on my symptoms and family history the doctor started me on 25mcg of eltroxin. My new results are TSH 1.73,FT3 5.3,FT4 14.7. I dont understand how my TSH can change so drastically yet the other two levels remained practically the same?can someone advise me as to what I should do or what this means!also I had an anti TPO tests and my result was 13.4!

Thank you for your help

2 Replies

TSH varies according to the time of day and whether you have eaten or not. Some people's TSH seems to be very sensitive to thyroxine as well. 25 is really a starter dose for the frail or elderly (usual starter dose is 50), so you should be getting an increase every 6 weeks or so until your symptoms are gone. Staying on a low dose for too long can make you worse, as your thyroid may give up producing the small amount of hormones it was originally able to.

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Hello sazziebunny,

Welcome to our forum and sorry to hear that you are not feeling well.

Thyroid Stimulating Hormone (TSH) is made in the pituatry gland and tells your thyroid how much T4 (thyroxine ) to make. Your TSH has dropped in response to your new meds. T4 & T3 are raising and can take longer to show. 25mcg Levo is a small dose & a TSH of 1.73 would allow for a further med increase.

A good result would be a low TSH and a higher T4 which the correct dose of thyroid meds should help accomplish and make you feel well again. The goal of Levothyroxine is to restore the patient to euthyroid status and for most people that means TSH just above or below 1.0. Be aware symptoms can lag behind good biochemistry by 6-8 weeks.

Levothyroxine takes up to 6 weeks to initially saturate the body which will only tolerate small increases at any one time. Your doctor should retest your thyroid hormone levels after 6 weeks and adjust the dose according to results.

Leave 24 hours between last dose and blood draw and try to have the blood draw early in the morning fasting ( only water) when TSH is highest.

It is important to take your pill on an empty stomach with a glass of water, 1 hour before food, 2 hours before supplements and 4 hours before calcium, iron or vit D supplements.

People with thyroid issues often have vitamin deficiencies and it is recommended that you have tests for B12, vit D, folate and ferritin as optimum levels are required to ensure thyroid meds are absorbed.

Depending on the range a TPOAb of 13.4 could be indicative of Hashimotos Disease which is prevalent in people with thyroid issues. Your aim would be to keep anybody levels low to reduce Hashi attacks. Many members (including myself) have found a gluten free diet to be beneficial.

I hope you feel better soon



This following link explains the importance of vitamins and where they may be obtained. This forum is supported by the charity ThyroidUK. You do not have to join the charity to benefit from this forum but by doing so you will be supporting the charity and also entitled to various discounts when buying supplements, as detailed in the link below.


Disclaimer: I am not a medical professional and this information is not intended to be a substituted for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


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