I'm 39. Can my TSH level change simply due to test timing?
Patient's Query
Hello doctor,
I am a 39-year-old woman with a history of sinusitis and nasal polyps. I usually have nasal blockage, but no known allergies. I am currently using Fluticasone nasal spray, nasal drops, and an antihistamine.
I have a question about my thyroid levels. My TSH (thyroid-stimulating hormone) has been fluctuating quite a lot over the past two years, even though I do not have clear symptoms of hypothyroidism apart from anxiety.
In the first test, TSH was 4.33 (test done in the afternoon).
In the second test, TSH was 7.06 (test done at 9 AM), my GP checked normal antibodies, and said no treatment was needed.
In the latest test, the TSH has now come down to 2.48 (again tested in the afternoon).
I am confused about why my TSH keeps changing so much. Could the time of day really cause so much variation, or is this normal? I have attached my results.
I also wanted to ask about my iron levels. My ferritin was borderline low. Should I be taking supplements or doing something to improve it?
Please help.
Thank you.
Hello,
Welcome to icliniq.com.
I have read your query and can understand your concern.
The change in your TSH (thyroid-stimulating hormone) levels from the second report (7.06) to the latest report (2.48), especially since one test was done in the morning and the other in the afternoon, can be explained largely by the body’s natural circadian rhythm. TSH naturally rises overnight and is highest early in the morning (around 2 to 4 am). It then slowly drops through the day, reaching its lowest levels by late afternoon or evening.
So, it is normal for a morning TSH to look higher than an afternoon TSH.
That said, your drop of about 65 percent is bigger than the usual day-to-day variation, but still possible. Natural hormonal fluctuations, mild temporary thyroid dysfunction, or even small lab differences can widen this gap.
In adults, TSH usually ranges between 0.4 and 4.0-5.0 mU/L, depending on the lab. Your latest report value (2.48) is well within this range. The second report’s value (7.06) was slightly above normal, suggesting mild subclinical hypothyroidism at that time. Since your thyroid antibody tests were normal and you did not start any treatment, the normalisation in the latest report could mean your thyroid was going through a temporary phase and then settled on its own.
About your iron results, a borderline-low ferritin level means your iron stores are on the lower side, but you are not anemic yet. It is a good idea to improve dietary iron and recheck levels. If you start having symptoms such as fatigue, hair fall, or restless legs, or if ferritin stays low, your doctor may consider starting an iron supplement. Low ferritin can also sometimes appear in people with thyroid fluctuations and may improve as thyroid levels stabilize.
I hope this answers your query.
Please let me know if I can assist you further.
Thank you.
Patient's Query
Hello doctor,
Thanks for your explanation, I understand. I forgot to add that my weight when the test with the 7.06 TSH was taken, I was overweight at 151 pounds. I have since lost 6 pounds, so my weight is about 145 pounds.
- Can being overweight cause increased TSH levels?
- Also, I was just curious if the hypothyroidism continues to be transient in the future, does it require treatment?
Kindly assist. Thanks.
Hello,
Welcome back to icliniq.com.
Being overweight can indeed be associated with modestly increased TSH levels. Studies have shown that higher body weight or body mass index (BMI) can correlate with slightly elevated TSH within the normal or mildly raised range, possibly due to increased demand on the thyroid or altered hormone metabolism.
Your initial higher TSH of 7.06 when you weighed 149.914 pounds compared to after weight loss aligns with this understanding, as weight reduction can sometimes lead to normalization or lowering of TSH levels.
Regarding transient hypothyroidism, if TSH elevation is mild, antibodies are negative, and thyroid function normalizes without treatment, it is often monitored without immediate medication.
Many cases resolve spontaneously, especially if caused by temporary factors such as illness, weight changes, or transient thyroiditis.
Treatment with Levothyroxine is generally reserved for persistent hypothyroidism (TSH consistently above 10 mU/L or symptomatic cases) or if thyroid antibodies are positive, indicating autoimmune thyroid disease.
If transient hypothyroidism recurs, regular clinical and biochemical monitoring is advised, and treatment decisions are individualized depending on TSH level, symptoms, and risk factors.
Overweight status can contribute to mild TSH elevation, and transient hypothyroidism without antibodies or symptoms often does not require treatment but close follow-up. Weight management can have a beneficial effect on thyroid function.
I hope I have answered your questions.
Revert in case you have any other doubts.
Thank you.
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