Thyroid Disorders Community
Some basic info about Thyroid labs & diagnosis of thyroid diseases
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This patient support community is for discussions relating to thyroid issues, goiter, Graves disease, Hashimoto's Thyroiditis, Human Growth Hormone (HGH), hyperthyroid, hypothyroid, metabolism, parathyroid, pituitary gland, thyroiditis, and thyroid Stimulating Hormone (TSH).

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Some basic info about Thyroid labs & diagnosis of thyroid diseases

I have noticed a lot of posts on this site with questions about thyroid labs, the difficulty in diagnosing thyroid issues, etc., and thought some of you might find this analogy helpful.

Your thyroid basically regulates your metabolism, which is the process your body uses to convert food into energy.  That means when your thyroid hormones are low, your metabolism runs slower than it should--which is why you get cold and gain weight and feel tired.  When your thyroid hormones are high, your metabolism runs faster than it should, which is why you are heat intolerant, have a rapid heart rate, and lose weight.

Now, here's the analogy.  Think of your thyroid gland like the furnace in a house.  It takes fuel (gas, electricity, whatever), and turns it into energy (heat).  The analogy is a little simplistic, but you'll see my point in a minute.

So, when you have a thyroid disease, your furnace is going haywire.

Now, how do doctors diagnose a thyroid disease?  Well, they listen to you describe your symptoms, then they order a lab test, usually for TSH, which is Thyroid Stimulating Hormone.  TSH is not used to regulate metabolism.  Its function is to control how much of the thyroid hormones your body makes.  So, back to our analogy--TSH is like the thermostat.  

So, if you are hyperthyroid (your body is making too much of the thyroid hormones), that's like your furnace running overtime.  When your furnace is running overtime and making your house too hot, you turn DOWN the thermostat.  So, LOW TSH numbers are associated with HIGH thyroid hormones, and vice versa.  When you have too much of the thyroid hormones in your body, the body sends a signal (by lowering the amount of TSH) to tell your body to stop producing them.

This analogy also might help explain why thyroid disorders are so difficult to diagnose just by looking at the TSH numbers.  There are two main challenges.  First, if you have a thyroid disease, your body is probably not obeying the signals it's getting via the TSH.  Just because the thermostat is set at a nice cozy 72 degrees doesn't mean it's actually going to be 72 degrees in the house if your furnace is acting wacky.  Second, the range of "normal" TSH values is pretty wide.  It's like saying as long as the thermostat is somewhere between 55 and 85, you're good to go.  

Different labs use different "normal" ranges for the TSH.  According to my endocrinologist, 0.3 - 3.0 is what he uses.  Some labs use even wider ranges.  I have seen 0.5 - 4.5 as the "normal" range several times on my lab reports.

Ideally, the TSH test would only be the first step.  If your doc looks at only the TSH and nothing else, it would be like the furnace repairman coming in and checking your thermostat and never even looking at the furnace itself.

To look at the furnace, your doctor should measure the levels of the two thyroid hormones themselves (T4, which often shows up as free T4 or FT4 on the labs, and T3).

If the hormone levels themselves are high or low, then the doc should work with you to find out why.  For example, Graves' disease is the most common cause of hyperthyroidism.  Graves is an autoimmune disease, so the doc can test for antibodies.  There is another common autoimmune disease that affects the thyroid as well, Hashimoto's thyroiditis, which usually make the patient hypothyroid (too low), so if you are hypo, the doc could check for those antibodies.

Let me know if you find this helpful--I could go into more detail on the autoimmune stuff in another post.  I have both Hashimoto's and Graves, which has been keeping my endocrinologist on his toes lately, so I have done quite a bit of research on it.

19 Comments Post a Comment
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Avatar_m_tn
Hello friend, thanks for sharing.  I read an article recently, stating that the autoimmune system is major cause of thyroid dysfunction.  Reason patients labs are normal, but continue to stay sick, cause autoimmune is overlook'd.  
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Avatar_f_tn
Hello
I am soooooooo blessed by both of your post. I have hashimotos and I am still not balanced.  My sinuses are a mess I have headaches, blurry vision, noooooo sex drive what so ever. Ok here is my concern, thyroid is discussed often, which by the way is very helpful, but I want to know about the autoimmuned aspect. When people have lupus, they are treated by doctors who specialize in auto immunity.  I think this is why we have to deal with idiot endo's ( not all, but some) who don't have a clue and can't explain it to their patients. I have a hard time understanding my thyroid because no one explained anything about the diasease to me. If it were not for you guys, I think I might be dead.  I know stress and diet triggered my antibodies. I remember the day it happened ( by the way that is all I remember because my memory *****). But not one doc said this is what is going on with you. This is probably why your sinuses won't heal, this is what is causing depression. Why is that. I'm still so confused and also, can your TSH be below normal if your t4 and t3 numbers are good? This is crazy. What happened to the day when you told your doc you were sick and they listened? Lastly, I an cytomel and levo. I know I have to stay on levo, but di I have to stay on cytomel forever? Why is it so hard to get answers. I told my husband that I think cancer would be easier, because at least your doctors would specialize in that area and could answer questions. I have soooo many question and have been doing so much research but still confused. Thank you for your post.  It was very, very, helpful.
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Avatar_f_tn
Sorry about the typos. iPad ;).
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Avatar_m_tn
Hi Toni, during my thyroid ordeal, only person that shared the truth was my radiologist performing CT scan, he say's the thyroid is a complete mystery.  

Answers are very difficult to obtain, specially via physicians/endo.  Most physicians/endos just try to treat symptoms opposed to discovering why a person became ill.  

I've learned alot through Dr. Rich Hagmeyer from Naperville institute website/articles.  He basically states most thyroid patients stay sick because physicians/endo, overlook root cause of thyroid disorder.  
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Avatar_f_tn
OMGosh Toni, I just found out I have Hashimotos also. I was talking to a firend and She said to ask the Dr about Amour Thyroid, I went on that 2 weeks ago. I feel much better but I am still tired. I could go to sleep at the srop of a hat. I also can't get out of bed in the am. I could sleep 12 hours and still be tired. Not sure what to do.
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Avatar_f_tn
Thank you for that post too. I have been looking and looking to find answers
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Avatar_f_tn
i wpuld rahter have anemia than have this disease i also had graves disease
for 20yrs, i am 55 yrs old had three rai,  2 rai didnt work the 3rd one did not its caused more  problems now, i have lost 25 pound i am 5'8 and 115pd
my tsh is extremely high and t3 and t4 are very low, i am now hypoglycemic and high cholesteral and firbmyalgia and low blood pressure and my right has constant ringing, i have trouble sleeping and they gave me sleeping med
my medicine is not working and i am on 1.25 mg and still feel very badly,i have been on every dose of levo thyroxine from 75mg to 250, i want to gain
weight but i am having problem keeping the weight i eat 5 small meals due to the hypoglycemia attacks which i have been gettin alot of them, i was wondering what blood test they can do if this is adrenal or putuitary gland problem
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Avatar_m_tn
I guess they will not allow an address? If interested PM
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Avatar_n_tn
After taking synthroid at a horribly large dose for more than 25 years, I. Finally convinced my primary care doc to test my PTH, went for a nuclear
Imagining yesterday, am awaiting results....thanks to all who shared their experiences....I' ll give you an update....honestly, what do thy teach them in med school.....?boo
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Avatar_f_tn
Hi there, I stumbled on your post and it's something I can relate to.

I had an abnormal blood test which showed my TSH at 5.2 with normal lab ranges between 2.0 and 4.2. I wasn't being tested for thyroid function at the time - it was for anaemia.

Unfortunately the clinic I was with did not tell me of this result. I called them a few days after the blood test to check back about it and they told me everything came back normal. I go to the doctors a couple of months later when I developed a very bad throat (sore throat, lost voice, bottom of neck swelled up). I put it down to a very nasty upper respiratory tract infection as I always have one at the start and end of each year.

The doctor went through my blood test results and casually said, "one of your thyroid hormones is a bit high," but then left it at that. She did say I looked as though I had a goitre, although I'm naturally slim and so the muscles in my throat/neck are probably more prominent.

So I get referred for an ultrasound on my thyroid, where the sonographer noted the gland itself looked a little "bulky" yet wrote to my doctor saying everything came back normal!!

Since then I've developed a lot of other problems - I sleep pretty much all day if I wanted to, flit between feeling happy and sad, experiencing early and late periods, pains in my stomach/chest and neck...I could go on.

I did go to two nurse practitioners, each were based at two seperate walk-in centres and both noted I had a small goitre. Of course I go back to my doctor to tell them of their findings and one doctor said that nurse practitioners don't have a better understanding of what a goitre is compared to a doctor's!!

So now I still get all these problems swallowing and I got so fed up with my doctor that I changed practices.

The thing is no one would suspect I have a thyroid problem, unless they took a good look at the small swelling in my neck and know straightaway it was a goitre. I get so self-conscious about it that I end up wearing a scarf or a snood around my neck to cover it up.

It's so frustrating to have to explain to those I know about my problems but more often than not it upsets me because I feel that I'm turning into a hypochondriac. I know something isn't sitting well with me, but I find myself getting fed up of telling the doctors that when they skirt around my question as to why the first blood test that started all this off came back abnormal!! They think that because I'm slim they're more likely to think of me being HYPERthyroid but when they look at the high TSH they don't do anything about it.

To this day I remain convinced that they should've put me on a T4 med - or at the very least done more to let me know about the abnormal result. You see, their protocol is to call the patient's phone number once and leave it at that.

You can probably see why I left them.

Thank you ever so much for your post -- at least I don't feel so alone knowing I'm not the only one with these problems.

Take care xxx
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Avatar_f_tn
Hi there, I'm suffering symptoms of subclinical hypothyroidism. Did it take a lot for you to convince your GP about being put on synthroid? My GP told me I had an abnormally high TSH and didn't put me on any medication at all, but since then I've been considering buying it online simply because it's taken all my energies to ask them to prescribe it for me.

Thanks for any advice!! xx
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Avatar_f_tn
Thanks so much for your post, Kirsten, very helpful....and all the responses have been helpful as well.  I've learned so much.  I went to Dr. Hagmeyer's site and learned about Estrogen dominance and how that can effect one's thyroid....very suspicious that the estrogen I've been on since my hysterectomy my have caused my thyroid problems.

Our nations health care crisis has made life difficult for doctors and patients, alike....this kind of sharing of information is so needed. Glad to be a part....this is my first post.
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Avatar_m_tn
You obviously need a good thyroid doctor.  By that I mean one that will treat you clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms, without being constrained by resultant TSH levels.  You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with after initial tests and evaluation.  The letter is then sent to the participating doctor of the patient to help guide treatment.  In the letter, please note the statement, "the ultimate criterion for dose adjustment must always be the clinical response of the patient."

http://hormonerestoration.com/files/ThyroidPMD.pdf

You might be interested to know that the AACE recently published the latest version of their guidelines for testing and treating potential hypothyroidism.  Then they posted it on Facebook and invited comments.  They really got blasted by a lot of hypothyroid sufferers for their advocacy of TSH as the test to use to evaluate for hypothyroidism and their use of "Reference Range Endocrinology" for the thyroid hormone tests.  In reply this is how they defended their position.  

"Well, it's been an interesting couple of days, with many of you taking the opportunity to express dissenting views. And, believe it or not, we thank you for that. But to clarify, the recent AACE/ATA Hypothyroidism guidelines do not state that TSH is the ONLY screening, just the best in most cases. The guidelines also state that "We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances."

Among many others, this was my response.

"While your guidelines also state that "We encourage medical professionals to use this information in conjunction with their best clinical judgement", somehow that gets totally lost in translation. It is very difficult to find a good thyroid doctor, that will treat hypo patients clinically. In spite of the inherent inaccuracy of blood testing, we mot often hear, " Your TSH is in the "normal " range, or your Free T4 is "normal", so your symptoms must be due to other causes. Millions of hypo patients suffer needlessly because of this misapplication of your guidelines. You could do all hypo patients a great service if you would clarify that the most important consideration in diagnosing and treating a hypo patient has to be symptoms, and that reference ranges for blood tests results should not be considered as pass/fail decisions, but as guidelines within which to adjust as necessary to relieve symptoms."

Being in the UK you have an even larger problem getting adequately tested and treated because of the NHS.  We have had many UK members with similar problems.  The best advice for getting the treatment you need
came from a fellow UK member.  

"What I have learned from my experience is that you have to go to the Dr's office and TELL THEM WHAT YOU WANT and to go backed up with knowledge.  You have to tell them that you have done your reading and looked into your condition and care about the long-term treatment of your health and thyroid.  If you fight for what you want, you will eventually find someone that is happy to go along with your wishes.  But we all have to take charge of our own health, right?"

The only other alternative seems to be to go private.  Wish I could give you a good thyroid doctor's name, but the only ones I have in the UK are located around London, or in the northern part.  





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Avatar_m_tn
Kirsten very well said on explaining the levels on how they measure the thyroid. I have Hashamoto's Thyroiditis as well as Multiple Sclerosis, Diabetes and now Rheumatoid Arthritis. My immune system failed me big time. With me all this started when I recieved a Hysterectomy at the age of 42. Now 10 years later now I'm 52 I'm still fighting. But I got lucky and was blessed with a fantastic Doctor. But it took me going through about 9 doctors to find him. I agree you have to be your own advocate and remember you are the boss you are the one hiring him or her. So if you feel they aren't listening to you or giving you the time of day then fire them & find one that will. Just don't give up.
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Avatar_f_tn
Hi there, thank you ever so much for your post. Because I'm now with a new doctor I can start over afresh. The problem with going private is of course money issues and I'm currently job seeking :( I've read up a lot about thyroid issues, checked out Wikipedia, googled it etc so I can go the doctors armed with some information. I never know, they might look back at my blood tests, see the TSH is high and put me on something straightaway, but then again how likely that's going to be remains to be seen.

Thanks for info and link!!

Lotus266012 x
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Avatar_f_tn
So I got tested and they said I was hyper but I was nursing and we opted to wait. I then was tested two months later and was hypo I know this is common after having a baby. But I feel hyper still. I been on the lowest dose of lex something its 25mg of it. I get chest pains like I am jogging sometimes or my thyroid hurts. I went to the gym ran five mins and got a heart rate reading of 167 It took an hour to get down to 131. Can they be wrong can you be hyper and have hypo days or times? should I see another doctor?
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Avatar_n_tn
I can see how that happens. They just push meds and never try to find cause...
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So who should one go to to find out what is going on with thyroid? What is normal what is not?
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Avatar_f_tn
Yes, you can go from hypo to hyper and back again.  Because I have Graves disease (which stimulates the thyroid) and Hashimoto's disease (which suppresses the thyroid), I go through cycles.

However, the cycles tend to be on the order of weeks or months--I would not expect to be hyper one day and hypo the next.  As we work to get the cycling under control, my doctor always waits two weeks after adjusting my medication before having me do another blood test.  It just takes that long for the thyroid system to adjust.

With regard to your medication, I can only assume you are talking about levothyroxine, otherwise known as synthroid, which is a synthetic replacement for the thyroid hormone and is used to treat hypothyroidism.

In your case, if you are having hyper symptoms, you should not be on levothyroixine AT ALL.  I am not a doctor, but if I were you, I would call my doctor immediately and tell them about your symptoms.  If you are hyper, levothyroxine is only making it worse, and the heart symptoms, in particular, can be dangerous.

If you are still working with your GP, you may want to consider requesting a referral to an endocrinologist.  An endocrinologist is better able to handle the more sophisticated thyroid conditions, such as mine, where the patient is experiencing hyper-hypo cycles.

Kirsten
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