I think this post gives excellent information about how to interpret lab results, and explains how to determine if your T4 to T3 conversion is sufficient (if on T4 only meds). That could be of particular interest to those of you on T4 only and not feeling optimally treated. In the Q&A section, the author also stresses the need to "put the thyroid to sleep" when treating Hashimoto's.
It's a shame not all doctors have an approach like this, but at least we as patients can educate ourselves:
PS. According to this online T4 to T3 conversion calculator, my ratio came back 18.9 and it should be >20. Anything below 25 means insufficient T4 to T3 conversion so basically hypothyroidism (regardless of the TSH).
OK, this is a tool for people on T4 only drugs, but I believe it can be applied to a person on NDT as well. My ratio came back showing not enough T3 (because is basically what this calculator tells us) on 3 grains of NDT. Interestingly enough, many problems indicative of hypothyroidism (rise in cholesterol and insulin resistance, weight gain and inability to lose it) have appeared on my current dose of NDT. That cannot be a coincidence.
Please could you post where to find the calculator, I have tried searching for it but can't find it. Many thanks in advance.
Its's in the article linked to in the original post but here is a copy paste of it:
To guide our initial dosing we use a proprietary ratio. What is the ratio of (free T3 in pg/ml)/(free T4 in pg/ml). The pg/ml is important because the free T4 is always reported inappropriately in ng/ml while the free T3 is often reported in pg/ml. Different scalar units. Multiple the Free T4 (ng/ml) x 10 = pg/ml so we can compare in similar units. A healthy ratio is >25%. A low and inadequate ratio is <20%. That infers poor conversion of T4 to T3 and the need for additional T3. If the ratio is >= 25% then a pure T4 is sufficient.
Example:
Free T4 = 0.91 ng/ml
Free T3 = 2.7 pg/ml
0.91 ng/ml x 10 = 9.1 pg/ml
So 2.7/9.1 = 29.6% (very healthy)
Many thanks
As if those of us on T4 replacement haven't got enough to worry about...
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