Aa
T4 to T3 conversion issue?
I have suspected for years that I had an issue with my thyroid based on empirical evidence. A couple of years ago my doc ran Free T3 and T4 and TSH. Everything was "fine" in the normal range. Started doing research. Went back to doc recently and asked him to run them again as well as Rev T3, Iodine, TPO and TgAB. Results are as follows:
Free T3 = 2.5 (ref 2.3 - 4.2)
Free T4 = 1.2 (ref .8 - 1.8)
TSH = 1.15 (ref .4 - 4.5)
Rev T3 = 10 (ref 8 - 25)
TPO = <1 (ref < 9)
TgAB = 16 (ref < or = 1)
So while all of my other numbers are in the normal range (maybe not where they should be) there is obviously some inflammation with the TgAB showing anything at all. Doc started me on 50 mcg Synthroid but how does one know if the problem lies in the conversion of the T4 to T3? If there is a conversion issue then just T4 is not going to help. Is there some formula for figuring if there is a conversion issue?
This is all very new to me. How does one determine if it is Hashi's or just plain old hypo? Thank you.
Free T3 = 2.5 (ref 2.3 - 4.2)
Free T4 = 1.2 (ref .8 - 1.8)
TSH = 1.15 (ref .4 - 4.5)
Rev T3 = 10 (ref 8 - 25)
TPO = <1 (ref < 9)
TgAB = 16 (ref < or = 1)
So while all of my other numbers are in the normal range (maybe not where they should be) there is obviously some inflammation with the TgAB showing anything at all. Doc started me on 50 mcg Synthroid but how does one know if the problem lies in the conversion of the T4 to T3? If there is a conversion issue then just T4 is not going to help. Is there some formula for figuring if there is a conversion issue?
This is all very new to me. How does one determine if it is Hashi's or just plain old hypo? Thank you.
Had an ultrasound of my thyroid today. Selenium getting checked next week when I have my re-test on the thyroid items.
Yes, Brazil nuts are little selenium bombs! LOL So much so, that I've heard a couple can be too much. It's always best to eat rather than take supplements.
It is pretty. After the extremely mild winter we just had, I might even be able to stay here a while longer! I do love it here, but the winters that last from October to June can be a little depressing. Sounds like a fun road trip...
It is pretty. After the extremely mild winter we just had, I might even be able to stay here a while longer! I do love it here, but the winters that last from October to June can be a little depressing. Sounds like a fun road trip...
Thank you so much! I will opt for the 4 1/2 weeks. I think I will also request a Selenium test and perhaps an ultrasound of the thyroid just for giggles. Never hurts to have a picture just to make sure there are no nodules.
I was also thinking that the meds might be interfering with conversion. I will keep you posted if I find anything else.
Did a little reading on the Selenium and find that if I do test low a couple of brazil nuts a day will probably take care of any deficiency.
BTW we are headed your direction in May. Driving to Chicago to see my Aunt and will be passing right by your area. Very pretty country out there.
I was also thinking that the meds might be interfering with conversion. I will keep you posted if I find anything else.
Did a little reading on the Selenium and find that if I do test low a couple of brazil nuts a day will probably take care of any deficiency.
BTW we are headed your direction in May. Driving to Chicago to see my Aunt and will be passing right by your area. Very pretty country out there.
Your FT4 isn't bad. It's at 40% of range. FT3 is at 11%, which is low. So, something is going on with conversion. It could be that your FT4 is just a little too low, and your body is "conserving" it by not converting as much to T3. This could resolve with higher FT4 level.
All T4 is made in the thyroid. It's the "storage" form of the thyroid hormones and basically floats around in your bloodstream until cells need thyroid hormone. However, cells can't use T4 directly. First, it has to be converted to T3. The enzyme (deiodinase) that catalyzes conversion (technically called deiodination) of T4 to T3 is a selenium based enzyme. So, a deficiency of selenium can impact conversion. However, you don't want to overdo it on the selenium. It's toxic if overdosed.
If I were you, I'd go for the 4.5 weeks...the vast majority has stabilized by then.
Have you tried googling each of your meds with "...and thyroid hormones", e.g. "sertraline and thyroid hormones". I found something about each of them interacting with thyroid hormones but nothing definitive. My money would be on the SSRI, though. If you find anything, let me know. I'd like to read it.
All T4 is made in the thyroid. It's the "storage" form of the thyroid hormones and basically floats around in your bloodstream until cells need thyroid hormone. However, cells can't use T4 directly. First, it has to be converted to T3. The enzyme (deiodinase) that catalyzes conversion (technically called deiodination) of T4 to T3 is a selenium based enzyme. So, a deficiency of selenium can impact conversion. However, you don't want to overdo it on the selenium. It's toxic if overdosed.
If I were you, I'd go for the 4.5 weeks...the vast majority has stabilized by then.
Have you tried googling each of your meds with "...and thyroid hormones", e.g. "sertraline and thyroid hormones". I found something about each of them interacting with thyroid hormones but nothing definitive. My money would be on the SSRI, though. If you find anything, let me know. I'd like to read it.
You are a welcome wealth of information. Thank you. Just started on the 50mcg a week ago. Am supposed to re-test 6 weeks from then but I will be gone so I'll either have to test at 4 1/2 weeks or 8 weeks. Have never had the selenium level tested. How does it play in to the whole equation?
Am on 10 mg Paroxetine and 50 mg Sertraline for the depression as well I take 25 mg HCTZ for edema which started oh maybe 5 or 6 years ago.
Am on 10 mg Paroxetine and 50 mg Sertraline for the depression as well I take 25 mg HCTZ for edema which started oh maybe 5 or 6 years ago.
That's interesting because while I could see your current labs, especially your very low FT3, causing those symptoms now, there's really nothing in the labs of two years ago to cause symptoms. FT4 was right about midrange where it belongs, FT3 was at 39% of range, which in my opinion is just fine for someone not on meds, TSH was very low.
Of course, we're all different, and some people need their numbers higher in the range than others.
How long ago did you start the 50 mcg of T4? When are you scheduled for retesting?
Have you ever had your selenium level tested?
Which meds are you on for depression? Some of them can impact conversion.
Of course, we're all different, and some people need their numbers higher in the range than others.
How long ago did you start the 50 mcg of T4? When are you scheduled for retesting?
Have you ever had your selenium level tested?
Which meds are you on for depression? Some of them can impact conversion.
Yes. Have been having symptoms for several years. Brain fog has definitely gotten worse as well as fingernail ridges and bags under eyes. Depression is controlled by meds. The rest have sort of been lifelong. I just started monitoring my basal temp so I can't speak to that.
So, when your labs of two years ago were drawn, were you already having these same symptoms? If so, have they changed at all?
Thank you Red_Star. Very informative.
goolarra - consistently low oral basal temp (96.9 - 97.1), fingernail ridges, fatigue, bags under eyes, trouble losing weight, headaches, cold hands/feet, poor eyebrow growth, depression, brain fog and a few more. These have not just come on. Have been struggling with them for years. Just trying to figure out what is going on.
goolarra - consistently low oral basal temp (96.9 - 97.1), fingernail ridges, fatigue, bags under eyes, trouble losing weight, headaches, cold hands/feet, poor eyebrow growth, depression, brain fog and a few more. These have not just come on. Have been struggling with them for years. Just trying to figure out what is going on.
So, your FT4 has dropped a little, even though it doesn't look like it has. Due to the very different ranges, it was 54% of range in the previous set of labs, and it's 40% now. FT3 went down considerably. TSH was on the low side two years ago, and now it's still very good.
RT3 isn't important by itself. What's important is the ratio of FT3 to RT3. Your ratio is 25, which is very good. It should be over 20. There are those who theorize that FT3:RT3 ratio is the best measure we have of tissue thyroid levels (which cannot be measured directly). I have very low FT3 (below range), but I am asymptomatic. My FT3:RT3 ratio is 23. My RT3 is also below range.
Tell me about your symptoms.
RT3 isn't important by itself. What's important is the ratio of FT3 to RT3. Your ratio is 25, which is very good. It should be over 20. There are those who theorize that FT3:RT3 ratio is the best measure we have of tissue thyroid levels (which cannot be measured directly). I have very low FT3 (below range), but I am asymptomatic. My FT3:RT3 ratio is 23. My RT3 is also below range.
Tell me about your symptoms.
Excerpts from Healthline - What Is an Anti-thyroglobulin Antibody Test?...
"Your thyroid is an endocrine gland located in your neck. It is responsible for releasing hormones that control your metabolism. The thyroid gland produces a number of different proteins, including thyroglobulin. This protein helps produce the hormones released by the thyroid gland.
The presence of an autoimmune system disorder can cause disruptions in how this protein is produced. Autoimmune disorders occur when your immune system begins attacking your healthy cells and tissues. When your immune system attacks thyroglobulin, a corresponding antibody is produced. This antibody is known as the antithyroglobulin antibody. The antithyroglobulin antibody test is used to measure whether or not you have this antibody in your bloodstream."
"Normal results for the antithyroglobulin antibody test are negative. This means that there are no antibodies present in your bloodstream. If you do have small amounts of the antithyroglobulin antibody in your blood, this may indicate the presence of certain health problems, including:
thyroid cancer
type 1 diabetes
rheumatoid arthritis, an autoimmune disease where your immune system attacks your joints
pernicious anemia, a decrease in red blood cells (RBC) caused by a vitamin B-12 deficiency
collagen vascular diseases, automimmune diseases that affect collagen, a connective tissue in the body; examples include rheumatoid arthritis and scleroderma
If you have high levels of the antibody in your blood, this may indicate additional health problems, such as the presence of serious autoimmune disorders, including:
Graves disease
Hashimoto thyroiditis
Though the presence of antithyroglobulin antibodies typically indicates a serious health problem, there are instances in which these antibodies are present without any specific complications. Antithyroglobulin antibodies have been found to increase in women as they age, but without any corresponding health problems.
If you have these antibodies with no underlying cause, your doctor may monitor your health and antibody levels to make sure that you do not develop any serious problems."
"Your thyroid is an endocrine gland located in your neck. It is responsible for releasing hormones that control your metabolism. The thyroid gland produces a number of different proteins, including thyroglobulin. This protein helps produce the hormones released by the thyroid gland.
The presence of an autoimmune system disorder can cause disruptions in how this protein is produced. Autoimmune disorders occur when your immune system begins attacking your healthy cells and tissues. When your immune system attacks thyroglobulin, a corresponding antibody is produced. This antibody is known as the antithyroglobulin antibody. The antithyroglobulin antibody test is used to measure whether or not you have this antibody in your bloodstream."
"Normal results for the antithyroglobulin antibody test are negative. This means that there are no antibodies present in your bloodstream. If you do have small amounts of the antithyroglobulin antibody in your blood, this may indicate the presence of certain health problems, including:
thyroid cancer
type 1 diabetes
rheumatoid arthritis, an autoimmune disease where your immune system attacks your joints
pernicious anemia, a decrease in red blood cells (RBC) caused by a vitamin B-12 deficiency
collagen vascular diseases, automimmune diseases that affect collagen, a connective tissue in the body; examples include rheumatoid arthritis and scleroderma
If you have high levels of the antibody in your blood, this may indicate additional health problems, such as the presence of serious autoimmune disorders, including:
Graves disease
Hashimoto thyroiditis
Though the presence of antithyroglobulin antibodies typically indicates a serious health problem, there are instances in which these antibodies are present without any specific complications. Antithyroglobulin antibodies have been found to increase in women as they age, but without any corresponding health problems.
If you have these antibodies with no underlying cause, your doctor may monitor your health and antibody levels to make sure that you do not develop any serious problems."
Thank you so much for posting.
T3 is in pg/ml
T4 is in ng/dL
Both greek to me
Yes the results two years ago were:
FT4 = .87 ng/dL (ref .6 - 1.1)
FT3 = 3.1 pg/ml (ref 2.4 - 4.2)
TSH = .5 uUI/mL (ref .4 - 4.6)
Yes I have seen that TGab are usually much higher than mine. Good idea to ask for a U/S to check. In my stats on my first post it was actually TPOab that was measured <1 (not TPO)
T3 is in pg/ml
T4 is in ng/dL
Both greek to me
Yes the results two years ago were:
FT4 = .87 ng/dL (ref .6 - 1.1)
FT3 = 3.1 pg/ml (ref 2.4 - 4.2)
TSH = .5 uUI/mL (ref .4 - 4.6)
Yes I have seen that TGab are usually much higher than mine. Good idea to ask for a U/S to check. In my stats on my first post it was actually TPOab that was measured <1 (not TPO)
Typically, if there is no conversion issue, FT3 should be higher (as a percentage of range) in its range than FT4 is in its. However, if FT4 is not about midrange, you can't make too many assumptions about conversion. So, right now, your FT4 is at 40% of range, and your FT3 is at 11%. It's probably worthwhile to get your FT4 up a little higher in the range and see if FT3 tracks it up.
What are the units your FT3 and RT3 are reported in?
As you know, the markers for Hashi's are TPOab and TGab. Only one has to be positive for a diagnosis of Hashi's. However, the vast majority of us with Hashi's are TPOab positive. It's only a small percentage that's only TGab positive. Some are positive for both. I'd also consider your TGab a "weak" positive. On diagnosis, many of us have antibody counts in the high hundreds or even thousands. TGab can be "somewhat" (a term that i have yet to see defined) elevated with other autoimmune diseases. So, you might ask for an U/S to see if the characteristic nodules are present.
Have you compared current results to those of a couple of years ago to see if there's a change?
What are the units your FT3 and RT3 are reported in?
As you know, the markers for Hashi's are TPOab and TGab. Only one has to be positive for a diagnosis of Hashi's. However, the vast majority of us with Hashi's are TPOab positive. It's only a small percentage that's only TGab positive. Some are positive for both. I'd also consider your TGab a "weak" positive. On diagnosis, many of us have antibody counts in the high hundreds or even thousands. TGab can be "somewhat" (a term that i have yet to see defined) elevated with other autoimmune diseases. So, you might ask for an U/S to see if the characteristic nodules are present.
Have you compared current results to those of a couple of years ago to see if there's a change?
Have an Answer?
You are reading content posted in the Thyroid Disorders Community
We tapped the CDC for information on what you need to know about radiation exposure
Endocrinologist Mark Lupo, MD, answers 10 questions about thyroid disorders and how to treat them
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Herpes sores blister, then burst, scab and heal.
Herpes spreads by oral, vaginal and anal sex.
STIs are the most common cause of genital sores.
