At what point does TSH start to rise?

[Snowdrop11]

I have been tracking my TSH, Free T4 and Free T3 for 2 years now, as my mom (who has Hashi's), encouraged me to get my TPO antibodies checked and they were found to be elevated (54 - ref range >50). I have many classic hypothyroid symptoms (fatigue, cold intolerance, brain fog, hair falling out)...so my question is this....my TSH has always fluctuated between 0.7 and 1.5 over the past 2 years. However, my Free T4 and Free T3 are slowly going down each time I get my blood work done (which is every 3 months). Latest results are as follows (Canadian units):

TSH - 1.5 (range 0.3 - 4.0)
Free T4 - 10.8 (range 9.0 - 23)
Free T3 - 3.6 (range 3.5 - 6.5)

So, my free T4 and free T3 are very close to the bottom end of the range, but my TSH is still normal. At what point should my TSH start to rise? Is there a magic T4 or T3 level where all of a sudden the TSH shoots up? I understand that secondary hypothyroidism could be considered, in which the TSH won't ever rise, but considering my TPO antibodies are elevated, that suggests Hashimoto's. My mom and grandma both had Hashimoto's so I feel like that is more likely the diagnosis. Oh, and my doctor refuses to treat me at this point as nothing is officially in the "clinical" range yet. Thanks for any insight on this!

[Red_Star]

Definition of clinical: relating to the observation and treatment of actual patients rather than theoretical or laboratory studies. Before the TSH test was used in 1973, doctors treated patients based on clinical symptoms. While the TSH has value, this test has flaws from the reference range itself to conditions that prevent TSH from rising in response to falling levels of thyroid hormone in the blood.

[Snowdrop11]

Thank you Red_Star...so if symptoms are present and my T4 and T3 are near the bottom of the range, it would be plausible for my doctor to offer treatment, regardless of the TSH level?

[Red_Star]

Generally speaking, the average doctor does not want to prescribe thyroid medication until labs are out of range.  Gimel (who answered above me) has a list of recommended doctors who may help you.

[gimel]

In Canada I expect that it won't be easy but you are going to have to feed your doctor enough information that conflicts with his training and inherent beliefs (not to mention the pressure from the NHS), to get him to read and re-consider what he has been doing for years, no doubt.  

Starting right from the definition of hypothyroidism, it is not just inadequate thyroid hormone.  Instead the correct definition is "insufficient T3 effect in tissue throughout the body due to inadequate supply of, or response to, thyroid hormone."   So diagnosis for potential hypothyroidism should not be based solely on biochemical tests.  There are no biochemical test that can be used as pass/fail decisions about a person's thyroid status.  The person's thyroid status is dependent on the level of Tissue T3 Effect.  So the best approach to diagnosis is  a full medical history, followed by an evaluation for signs/symptoms that occur more frequently with hypothyroidism than otherwise, and then extended biochemical tests.  The tests that are necessary are Free T4, Free T3, TSH,  Reverse T3 at least at the beginning, cortisol, Vitamin D, B12 and ferritin.  

The most important diagnostic is the signs/symptoms I mentioned.  TSH is useful as a diagnostic only when at extreme values.  Intermediate values for TSH  have only a weak correlate with the biologically active thyroid hormones, Free T4 and Free T3, and a negligible correlation with Tissue T3 Effect which represents the patient's thyroid status.    So how is it supposed to magically represent a person's thyroid status?  Clearly it does not.  

In using Free T4 and Free T3 for assessment, you have to take into consideration that the reference ranges are so flawed, and skewed to the low end, due to the erroneous assumptions used to establish them.  FT4 and FT3 have only a weak correlation with Tissue T3 Effect.  

Reverse T3 in excess can adversely affect Free T3.  High or low cortisol can also affect Tissue T3 Effect.  Also, Vitamin D, B12 and ferritin fall into the category of affecting response t thyroid hormone.

There is more to discuss, but I have to leave for a while.  When I return I will provide more info.  In the interim I suggest that you click on my name and then scroll down to my Journal and read at least the one page overview of a full paper on Diagnosis and Treatment of Hypothyroidism: A Patient's Perspective.