Thyroid UK
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Ambushed by blood test - now what should I do?

I have been on Thyroid S for a tear now, gradually rising to 2.5 grains. All appears well except for the fact that the last twice I have had a virus, I have had tachycardia with it.

My usual GP was not bothered by this, but I saw one if his colleagues last week who picked up that my thyroid had not been checked for nearly eighteen months and ordered a TFT.

Without thinking, I got it done the same morning, four hours after I had taken one grain of Thyroid S. The results came back as:

TSH <0.02 (0.27-4.2)

FT4 27 (9-26)

I managed to persuade him that the suppressed TSH was not significant, but of course the FT4 was over range so he has asked me to reduce my dose. He thinks I'm still on Levo, so he said drop from 125 to 100.

I suspect that if I had taken no meds since the previous morning, as would normally be the case for a blood test, my FT4 would have come back well within range, so I'm kicking myself now.

The tachycardia has disappeared with the virus, but the GP will now congratulate himself on being right that it was my thyroid. I have no signs of over-replacement now. I really need to speak to him about whether I am always going to get tachycardia now with a virus, what I should do about it when it happens etc, but I seem to have shut that door.

I swapped to Thyroid S to regain control of my situation because I could not get enough Levo off the GP or more than 28 days' supply at a time.

5 Replies

Ansteynomad, It's very likely FT4 is mildly elevated because you took your NDT before the blood draw. I wouldn't reduce NDT dose for such mild elevation anyway.


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

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Well, you could try coming clean about the Thyroid S, and explain what happened with the blood test. What can he do? Shout a bit but not much more. Although I very much doubt he will know anything about the virus and the tachycardia.

Or, you could ask to be referred to a cardioligist, and see if he can help you.

In future, it would be better to refuse tests that are just sprung on you like that. Doctors really shouldn't do that, but they Don't know about TSH lowering after taking a dose and/or eating and/or doing blood tests late in the day. Just say it's not the right time, I'll come back in the morning.

Or, ask for another test. Say you didn't lower your dose because you didn't think you were over-dosed, because you'd taken your hormone that morning. And, before you consent to lower your dose, you want a test done Under the right circumstances.

Lots of things you can say, really... :)

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Just keep to the same dose you were on as your test after taking dose would definitely skew your results.

I've done the same on T3 only and GP was startled when he looked on the screen but just as he was doing so I told him to ignore anything about the blood tests and please let me have another. I told him the bloods would be skewed. He was happy with my next test and everything has been fine. Now, the day before a test I put T3 elsewhere so I'm not on automatic pilot in the morning also put an alarm too.

You don't have to say what you are taking because it should level out. They only take T4 and TSH usually.


shaws..what is your free t3? Is your TSH suppressed on the dose that you take of t3? Mine is very suppressed. 0.003.


FT3 is 6.5 (2.60-5.70pmol/L (satisfactory - No action)

TSH 0.46 (0.35-5.00) Normal - No action.

with 24 hours between last dose and test taken 2 weeks ago.

The results of my test one week later when I took T3 before it was:

FT3 14.9 - so the following week- just so I wouldn't have T3 withdrawn I allowed around 48 hours between last dose and test which gave a result of 3.8.

So it shows how important it is not to have a blood test just after taking thyroid hormones.

Re suppressed TSH From Dr L who only took tests for the first appointmentL. He of course took other measurements, i.e. tissue etc.

"You may find it helpful to keep in mind a clear-cut double standard of the endocrinology specialty. Endocrinologists keep thousands of thyroid cancer patients on TSH-suppressive doses of thyroid hormone. But these specialists vociferously warn of grave dangers if hypothyroid patients use the same TSH-suppressive doses. However, meta-analyses of studies show that these doses are harmless to thyroid cancer patients, despite them staying on the doses for decades. Rather than harming the cancer patients, TSH-suppressive doses appear to benefit them: researchers write that the patients report feeling better on these doses than hypothyroid patients do on T4-replacement. (In T4-replacement, of course, the patient uses a dose of thyroid hormone that doesn't suppress the TSH.)

The endocrinology specialty cannot reconcile this discrepancy in its practice guidelines for the two different groups of patients. This to me is one of many pieces of evidence that T4-replacement is driven by commerce—not by science or an aim for therapeutic effectiveness. I provide rock-hard evidence for this conclusion in my forthcoming book Tyranny of the TSH."


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