Thyroid tests

[Devonlaraa]

Why is it suggested by many on here that bloods should be taken early in the morning? Just curious as I recently had a test and I took it in the afternoon and the results came back borderline.

[greygoose]

Because TSH is highest in the morning, and after fasting all night. And, as doctors only look at TSH, you want it as high as possible.

If you were 'borderline' in the afternoon, you would probably have been diagnosed hypo, had you had your test at 7.0 am and fasting.

[shaws Administrator]

If you had had your test in the morning, it might have raised your 'borderline' to non-borderline, i.e. hypothyroidism.

Doctors only take notice of the TSH (Thyroid Stimulating Hormone) which is from the pituitary gland which tries to increase our thyroid gland to produce more hormones, so therefore the TSH rises which shows thyroid gland is struggling.

The TSH is highest very early a.m. and drops throughout the day so a a very early appointment might make the difference between being undiagnosed and diagnosed..

[Devonlaraa]

Oh brilliant thank you. I'll go back to my doctors then and see if I can get another test done. They told me to continue on the dose I'm on even though I still have a lot of the symptoms I had on my previous dosage.

[greygoose in reply to Devonlaraa]

Did you leave a 24 hour gap between your last dose and the test? If you don't do that, your FT4 will be too high.

[humanbean]

Look at the graphs on page 2 of this paper :

press.endocrine.org/doi/pdf...

It explains how the TSH, Free T4 and Free T3 alter throughout the 24 hour day. This shows why getting a blood test as early in the day as possible gets the best result.

Eating and drinking allegedly reduces TSH. So don't eat and drink in the morning before your blood test, although water should be drunk freely. I'm not convinced by the evidence for this but I fast for tests anyway because it makes it easier to compare results if we keep conditions the same for all tests.

Take your last dose of Levo 24 hours before the blood test is due. Then take any missing doses after the blood is taken.

[infomaniac in reply to humanbean]

Those graphs are very illuminating humanbean, thanks a lot. I get in from work about 2pm then have something small for lunch and I generally feel absolutely knackered by 3pm but could never understand why. So now it looks like it's because of the massive dip in T3 is there anything I can do to counteract this? (I am on Levo only)

[humanbean in reply to infomaniac]

Don't be fooled by the way the graphs are drawn. The scale on the y-axis is not the same on all the graphs.

The difference between minimum and maximum T3 is really very small.

This is not true for TSH where the difference between minimum and maximum is big enough to make the difference between being told you are hypothyroid or not hypothyroid.

I think the dip in energy is common to everyone in the afternoon and is why some cultures have customarily had a siesta in the afternoon.

I realise that it can be extreme though. I've suffered the post-lunch dip in energy levels myself for most of my life. It varies in intensity depending on how well or ill I am.

The things I've personally found that make a difference are :

1) Timing of thyroid med dosing. Perhaps you could experiment with taking your Levo at the opposite end of the day to when you currently take it. I found timing makes a huge difference when taking T3, but I haven't spent very long on Levo, so can't say if it will make much difference to you. But it is an experiment worth trying.

2) Cortisol spikes or dips could have a huge impact on how you feel in the afternoon. Do you know anything about your cortisol levels during the day? Have you done a saliva test?

3) I have found that eating more helps me. I developed a habit many years ago of eating only twice a day, and breakfast was invariably a carb-heavy meal. Now, I am spreading my food intake over more of the day, I'm eating more, and I eat more fat, more protein and less carbs. I don't eat a low-carb, high fat diet, but I do eat a lower carb, higher fat. This suggests to me the problem of the post-lunch dip is something to do with insulin output and blood sugar. But it isn't a subject I know anything about so I can't explain it, I just know the effect of food on low energy is very real and that altering my diet has reduced the problem to some extent. I'm still working on it.

Sorry I can't give you anything other than personal anecdote.

[infomaniac in reply to humanbean]

I had thought while ago that it might be due to low blood sugar so was taking a snack to work,but it didn't make much difference. Just thinking more about it, I don't really crash out at the weekend so maybe it's just a case of needing a rest? I'm absolutely knackered at the moment and am waiting for my Blue Horizon test kit to come to see if I can work out what's going on. I even had a weird dream last night about having to play a ball game lying down because I was so tired!!