need help to interpret labs...?

Ok, so I wanted to ask you about labs...24 h urine analysis to be more exact. I am seeing a doctor in Belgium trained by Thierry Hertoghe, and all the Hertoghe docs work with 24 h urine as well as blood...

However, they seem to agree that the T3 and T4 levels in 24 h urine are more telling than thyroid hormone levels in blood.

Anyway, when I first went to see my hormone doctor, I was on 200 mcg of thyroxine. Feeling pretty OK all in all, but unable to lose weight, bloated, retaining fluid...

Labs showed the following (on 200 mcg of thyroxine):

Blood:

FT3 2.2 (ref 1.8-3.8)

FT4 1.1 (ref 0.7-1.5)

TSH <0.001 (ref 0.2-4.0)

24 h urine:

T3 824 (ref 800-2000)

T4 1200 (ref 1100-2500)

Now, I am wondering: given my results above, should I interpret this to mean that

1. I don't convert T4 to T3

2. both my T4 and T3 levels were way too low on thyroxine only, even on as much as 200 mcg daily (which is quite a lot after all), and this means that I need more T3 AND T4? But does anyone need more than 200 mcg of T4 daily?!

[Clutter]

Thecat, your TSH is very suppressed, your FT4 serum half way through range and your FT3 serum under half way through range. Suppressed TSH can impair T4 to T3 conversion. I think you probably need some T3 added to a reduced dose of T4. On 200mcg one would expect to see suppressed TSH but FT4 in the top 75% of range. People need as much thyroxine as they need and there are members on more than 400mcg daily.

I'm not very familiar with thyroid urine tests but your FT4 and FT3 are both low in range.

[faith63 in reply to Clutter]

How does suppressed TSH impair conversion? Conversion is done in other areas, not the Thyroid Gland itself. Do you have any documentation? I do not convert well, have a suppressed TSH and have since starting thyroid meds.

Thanks

[helvella Administrator in reply to faith63]

So far as I am aware, and I would be happy to be told otherwise, we do not have a complete understanding of precisely how T4 -> T3 conversion is controlled. (There might even be different control mechanisms for the liver and for cells which perform their own conversion.) Any number of things could affect that - possibly including TSH level.

Rod

[Clutter]

Thecat, just found this on urine testing:

A study of 832 hypothyroid patients showed that 24 hour urine Free T3 had the highest inverse correlation with clinical symptoms. In other words, the higher the urine Free T3, the lower the symptoms and vice versa. Urine Free T3 is not influenced by binding globulins and correlated well with the severity of eight clinical hypothyroid symptoms: fatigue, depression, coldness, headache, muscle cramps, constipation, arthritis, and Achilles tendon reflex. Serum T4, Free T4, and TSH often had no correlation to these symptoms. [24]

tiredthyroid.com/tsh.html

[Hidden in reply to Clutter]

Thank you, Clutter, very interesting indeed!