Why Efforts to Harmonize Testing Are Critical to Patient Care
I had added this to another post and I'm afraid it got lost. There are some interesting statements in this article that Thyroid Patients should be aware of. PR
"Based on the functional interrelationship of the hypothalamus, pituitary gland, and thyroid, TSH should be elevated if the thyroid gland is not producing adequate thyroid hormone, and suppressed if it is producing too much (Figure 1). Today, however, we are beginning to realize that this well-established paradigm for TSH synthesis and release is an oversimplification."
"Although laboratory measurement of serum TSH is an essential tool for diagnosing and managing various thyroid disorders, the laboratory medicine community has long recognized that immunoassays used to measure the hormone are yet another source of variability in patients’ results."
"The upper limit of euthyroidism with first-generation TSH assays was approximately 10 mIU/L, but with the introduction of second- and third-generation assays it fell to approximately 5 mIU/L. The most likely reason for this change was the reduced cross-reactivity afforded by the monoclonal antibodies used in the newer assays."
"there is growing consensus that one TSH reference interval does not fit all."
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PR4Now, I'll have to read it again as I got a bit lost but am I right in saying that this moves us closer to what Diogenes said, that TSH is individual?
thyroiduk.org.uk/tuk/TUK_PD...
Clutter, that is a good question, hopefully Diogenes will add his insight. It sounds like it to me but without talking to Dr. Thienpont, which is unlikely, I wouldn't want to say that is a given. But at least Dr. Thienpont is acknowledging some pertinent points.
The TFTs will still suffer from a 'low index of individuality' which was partially acknowledged by the statement "individuals appear to have their own set-points, and factors such as race and age also contribute to variability in TSH levels." There have been six studies that I know of regarding the 'low index of individuality' of the TFTs, the first in 1986. The underpinning work on this goes back to the 1950s, at least. The most often quoted study is Anderson et al. from 2002. He measured 16 healthy individuals once a month for 12 months and plotted their own individual 95% reference range for the TSH, TT4, TT3 and FTI. One was excluded because it was thought he suffered from mild hyperthyroidism. The width of the individual Reference Ranges for TSH for the remaining 15 varied from 0.32--2.35 units wide, with the average being 1.13 units wide. Because we all have our own unique individual set point, based on our genetics, epigenetics and metagenomics, each persons' set point was slightly different. The group RR was 0.16-2.39 uU/mL. So if you are an individual with a narrow 95% RR and a low set point you could move 2 or 3 full points and still be in the "normal" range. You don't show up on the Thyroid Function Tests until the extremes. They are anything but 'highly accurate' for an individual, at best they are a rough clue. They know there is a ballpark but they have absolutely no idea where home plate is for any given patient. What science doesn't have any understanding of is how far do you have to move off your own set point to cause problems. Dr. Anderson thought a move of 0.75 was significant. As we have discussed previously, many of us feel that the longer it takes to get adequate treatment the more damage that can be caused, quite often changing a person's own set point.
This is a short presentation from 2003. You have to use a PC and you have to use IE. If it doesn't start right away, it takes a minute or so to start. It is only about 17 minutes. They also knew the FT3 test was a mess back then, it wasn't a secret. PR
site.blueskybroadcast.com/C...
i remember reading somewhere - cant remember where - of a large study in turkey that positively sought healthy and no family history of anything metabolic that found it was just under 1 for tsh. this seemed supported by my frien who recently had tsh test as tired and hers was 1.0 - she had low iron that was her health problem that was easily resolved with supplements. what about this research anyone else know of it?
Generally speaking, the mean for the TSH is usually between 1.0 and 1.5 in many studies. This can vary due to iodine and/or selenium deficiency, race/ethnicity and somewhat by age. Other factors like low iron, B12, folate, Vit D, Cortisol, stress, diet, environmental toxicity and autoimmunity can affect individuals just like your friend whose TSH was 1.0 and yet she was tired because of low iron. I also suspect that thyroid hormone resistance is more prevalent then commonly recognized. PR
I have a hunch that having a pituitary that doesn't put out quite as much TSH (and possibly, other hormones) as would appear appropriate is another major issue. Not talking about it being so severe as to call it hypopituitary - just that when it perhaps "should" be pumping out enough to get a TSH reading of, say, 10, it is only ever reaching 5. Possibly in the range up to, pick a number from the air, 3.0, it is fine, but it won't go much higher.
Rod
Rod, thanks for adding that. AS often as it is mentioned here you would think I would have remembered that point. PR