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What Is The Ideal Synthyroid Level When TSH Is 3.65?
Question: My mother is 85 years old and she has been taking 50mg and 25mg of Synthroid on alternate days ie 37.5 mg on an average per day. Her lab results indicate Free T4 is 1.59 which higher than normal and TSH is 3.65 which is on the high side. Generally High TSH should indicate lower Free T4 and higher Free T4 should result in lower TSH. In her case both seems to be on the high side. What could be the reason and what should be Synthroid medication dosage for her. Thanks for your help
Brief Answer:
No. Both are normal report. Continue same dosage.
Detailed Answer:
Hello welcome to HCM.
I have read your question and understand your concerns.
Your both free T4 and TSH levels are within normal limits. Kindly reconfirm your reference range.
I will give you normal reference ranges.
Free T3 - 2.3-4.2 pg/ml.
Free T4 - 0.8-1.8 ng/ml.
TSH levels - 0.5-4.7 mu/ml.
In Hypothyroidism usually we follow serum TSH levels only. Your TSH levels are within normal limits. So my advice is continue same dosage of thyroxine medicines. No need to change dosage of thyroxine.
Usually when Low dosage of thyroxine has been given the TSH levels will be high and if over treatment of thyroid leads to low levels of TSH levels.
I hope I have given you satisfactory answer, if you have any questions you are always welcome.
Thank you.
Have a nice day.
No. Both are normal report. Continue same dosage.
Detailed Answer:
Hello welcome to HCM.
I have read your question and understand your concerns.
Your both free T4 and TSH levels are within normal limits. Kindly reconfirm your reference range.
I will give you normal reference ranges.
Free T3 - 2.3-4.2 pg/ml.
Free T4 - 0.8-1.8 ng/ml.
TSH levels - 0.5-4.7 mu/ml.
In Hypothyroidism usually we follow serum TSH levels only. Your TSH levels are within normal limits. So my advice is continue same dosage of thyroxine medicines. No need to change dosage of thyroxine.
Usually when Low dosage of thyroxine has been given the TSH levels will be high and if over treatment of thyroid leads to low levels of TSH levels.
I hope I have given you satisfactory answer, if you have any questions you are always welcome.
Thank you.
Have a nice day.
Above answer was peer-reviewed by :
Dr. Bhagyalaxmi Nalaparaju
Dr Vora,
Thanks for your feedback and appreciate it.
You have stated normal range for Free T4 level to be 0.8 - 1.8. In the lab results it had indicated Free T4 as 1.59 (High) and the range was 0.6-1.2. TSH in the lab results is 3.65 but according to you it is within the normal range so it is ok.
Last year I was told by an endocrinologist that it is better for TSH to be below 2 and Free T4 below 1.2 and hence I was inquiring from you.
So I should not lower the Synthroid dosage to 25mg everyday but based on tour recommendation should keep the current dosage of 37.5 mg per day as both the results for TSH and Free T4 are normal.
Please confirm and thanks for your help.
XXXX
Thanks for your feedback and appreciate it.
You have stated normal range for Free T4 level to be 0.8 - 1.8. In the lab results it had indicated Free T4 as 1.59 (High) and the range was 0.6-1.2. TSH in the lab results is 3.65 but according to you it is within the normal range so it is ok.
Last year I was told by an endocrinologist that it is better for TSH to be below 2 and Free T4 below 1.2 and hence I was inquiring from you.
So I should not lower the Synthroid dosage to 25mg everyday but based on tour recommendation should keep the current dosage of 37.5 mg per day as both the results for TSH and Free T4 are normal.
Please confirm and thanks for your help.
XXXX
Brief Answer:
Yes. Kindly give same dosage.
Detailed Answer:
Hello welcome to HCM again.
As per my opinion your thyroxine dosage is adequate and no need to change it because both of reports are within normal range.
Always do thyroid profile in Fasting because Free T3, T4 levels might alter.
Secondly if you lower the dosage then the TSH levels will go more higher and will be truly abnormal and she will again feel symptoms on Longterm. So reducing the dosage is beyond question.
So, maintain same dosage and reconfirm with laboratory person about normal reference range.
Normal value ranges may vary slightly among different laboratories.
You can repeat thyroid profile after 15-20 days in Fasting and ask me again if necessary.
Thank you. Have a nice day.
If you have any questions then you are welcome otherwise Kindly rate the answer.
Yes. Kindly give same dosage.
Detailed Answer:
Hello welcome to HCM again.
As per my opinion your thyroxine dosage is adequate and no need to change it because both of reports are within normal range.
Always do thyroid profile in Fasting because Free T3, T4 levels might alter.
Secondly if you lower the dosage then the TSH levels will go more higher and will be truly abnormal and she will again feel symptoms on Longterm. So reducing the dosage is beyond question.
So, maintain same dosage and reconfirm with laboratory person about normal reference range.
Normal value ranges may vary slightly among different laboratories.
You can repeat thyroid profile after 15-20 days in Fasting and ask me again if necessary.
Thank you. Have a nice day.
If you have any questions then you are welcome otherwise Kindly rate the answer.
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Above answer was peer-reviewed by :
Dr. Bhagyalaxmi Nalaparaju
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