Since hypo thyroid and lyme or co-infections have overlapping symptoms (many are the same), its hard to tell them apart unless your thyroid is at optimal levels.
Based on this current test of yours, your not even at the mid-point of the Free T ranges so your not optimal and still a little hypo..
**It does take 6 weeks for the slower acting T4 to be accurately measured, T3 is faster **
Your Dr is probably treating you with TSH as being most important, but the frees are actually most important and you can still bump them up a little and then watch the TSH drop more down to 1 or so. Many people aim for and feel better at 2/3 up in the free ranges. Usually the FT3 will be a higher ratio that FT4 when using pig thyroid, Im surprised your is not. Usually FT4 lags a little lower than FT3 from NDT.
TSH 1.74 - Ranges 0.32-4.00 mIU/L
FT4 12 - Ranges 9-19 pmol/L - the midpoint is 14, your at 12
FT3 3.7 - Ranges 2.6-5.8 pmol/L - the midpoint is 4.2, your at 3.7
When on thyroid medication, the TSH will always be lower. If you had those same free values but without thyroid med, the TSH would be higher; (more hypo).
Note: its also a good idea to differentiate between regular hypothyroid and hashimoto hypothyroid, hashi will test with elevated antibodies of either or both of these tests : TPO and TgAb - get these tested. If you have hashimoto, 100% (not 90%) gluten free will help. I was a non-believer till I did it and saw improved results.Hashi is an inflammatory condition, and gluten somehow inflames the thyroid in some individuals - especially those prone to gut issues.
.
Post Edited (astroman) : 10/11/2019 11:08:20 PM (GMT-6)