What does the TSH3UL test measure?

[pam319blue]

I have been treated with Synthroid for Hypothyroid for 2 years.  I had radium treatments on my ears as a child which is probably the reason.  Because I am still tired, though not as tired, and almost unable to lose weight, my endocrinologist checked my blood again and results of those checks and ranges from lab follow:

FT4   1.57  (Range 0.61-1.76) ng/dl
TSH3UL   0.27   (Range 0.55-4.78) mIU/ml

Can someone explain what these mean, especially the TSH3UL?  I assume since T4 should convert to T3 or something like that - that there was a reason for doing them together.  I got the results by mail today, and I am simply to return in August for my next appointment.  I like the physician, but I do want to know what these values mean to me and why they are pertinent.

Thanks for any info.  

[Barb135]

Everything you're saying makes sense, but that doesn't mean I agree with the way your doctor/nurse are handling your case.  

FT3 is the hormone that controls metabolism (and other functions) and they're telling you to go lose some weight, when they don't even know if your metabolism is conducive to weight loss or not.

I don't have a problem with your TSH being 0.27, because TSH is often low or suppressed when on a thyroid replacement medication; mine stays at < 0.01.  TSH is a pituitary hormone and does not correlate with symptoms. Because your FT4 is so high in the range, I'm afraid you aren't converting enough to FT3 to alleviate your symptoms.  The only way you can know is to get an FT3 test.

In my opinion, you either need to get this doctor to run an FT3/FT4 or get someone else to do it.  You can also order those tests online without your doctor, if you have no other options.  I've done that before.

[pam319blue]

Barb, I talked to my doctor's nurse this morning.  She said that I did not need a change in my thyroid medicine and that the FT4 that I recently had was a Free T4 and it was 1.57 out of a lab range of (Range 0.61-1.76) ng/dl
She also said that when I first saw him my TSH was .025 and got up to
1.31 but I was still having symptoms.  So now it is .27, and he does not think any symptoms are from my thyroid.  She suggested that when I have lost a little weight to call and make an appt and ask that these values be tested again on my thyroid, including the Free T3.  Does all this make sense to you AND do you think being Hypo and having a TSH of TSH3UL   0.27   (Range 0.55-4.78) mIU/ml makes sense.  I do feel better than I did but not like I used to feel.  I understand what you are saying in that all of my Free T4 may still not make enough FT3 for me. Thank you for helping and please let me know your thoughts this time.

[pam319blue]

I talked with doctor's nurse yesterday.  My TSH was 1.31 when I first went in and had symptoms plus some nodules that were suspicious and were biospied.  The nurse said that as my TSH went down and so that the TSH3UL was actually good for me -  0.27   (Range 0.55-4.78) mIU/ml
- though it seemed backwards.  I asked, and I have never had a Free T3 and am not sure about the Free T4 unless the test I had for FT4 as
FT4   1.57  (Range 0.61-1.76) ng/dl  is Free T4.  The nurse is speaking to the doctor and will return my call.  I am reading a couple of books about Thyroid trying to learn more as it is complicated.  I will ask for a blood test for both Free T3 and Free T4 and after those see if adjusting dosage again is indicated.  Thank you for your help.  I wish that there was a simple 2 page handout to explain this.  I am reading the Gottfried Hormone Cure book which does have an understandable chapter on Thyroid.  

[Barb135]

Have you ever been tested for the actual thyroid hormones, Free T3 and Free T4?  If so, please post results, with reference ranges (those vary lab to lab and have to come from your own report).  Your symptoms still sound hypo, indicating that you need a further increase in your medication.

Hair loss is typically a hypo symptom and anxiety can arise when increasing medications.  How long did you remain on the 100 mcg? It's not unusual for symptoms to get worse when increasing med.

You might ask if you could try alternating 75 mcg/day with 100 mcg/day, for an average of 87.5.  Would be a daily increase, but not so much.

[pam319blue]

I was told Hypothyroid as when diagnosed I had some bad nodules which were biopsied.  Most of the caution is due to the radium exposure as a child.  The endo ran a lot of blood work and basically said that I had almost a non-functioning thyroid.  Fatigue was my biggest problem, but I have also gained weight and it seems almost impossible to shed.  The doctor gave me Synthroid (not the generic), and I have ended up at 75 mg. 5 days a week and 100 mg on Sat. and Sun.  75 is in form of 1 50 mg and 1/2 50 mg because I got headaches on the 75 which he told me happens with the dye.  100 all the time makes my hair fall out and gives me an anxious feeling.  I believe that this thyroid issue has been present for quite a while as at least once or twice per year I got an awful rash which was usually attributed to some medication like an antibiotic - however, none since I began Synthroid two years ago.  My skin and scalp have also been bad, and my skin and scalp have improved but scalp not as much as skin.  The weigh really bothers me, and I am getting ready to try the Virgin Diet just to see if eliminating some items might help as I expect dairy and gluten to be problematic.  I am not absolutely sure that my endo is a thyroid expert as much as a diabetes expert, but he gets rave reviews from patients and listens, etc.  While I consider myself to be medically savvy, I have not pushed for answers like I should, not have I read everything because the whole issue seems overwhelming.  I am 66 years old.  My mother had thyroid disease in her 70-80s but she was in radium room with me too.  I appreciate your information and assistance.  

[Barb135]

TSH is Thyroid Stimulating Hormone, 3rd generation, Ultra.  TSH is a hormone produced by the pituitary gland to instruct the thyroid to produce more thyroid hormones, T4 and T3.

The thyroid produces mainly T4, some of which is bound by protein and is unavailable for us.  The part that's unbound, is what's available to be converted to T3.  The unbound portion is the Free T4.  

Thyroid tests are usually done together in order to give a fuller picture of what's going on at that particular time.  It's too bad your doctor didn't order a Free T3, with the FT4 and TSH, since FT3 correlates best with symptoms.  Some of us don't convert FT4 to FT3 adequately, so we have to add a source of T3 to our regimen.  The only way we can know is if we have FT3 tested. Next time you have blood work ask your doctor to add it to the lab order.

What medication/dosage are you on?  Do you have symptoms of either hyper or hypothyroidism?