A couple of good comments already. Hashimotos is diagnosed based on the presence of antibodies which are attacking your thyroid. Now, depending how long that's been happening, your thyroid may or may not be still producing the necessary hormones. Which is why they also look at thyroid production levels (typically T4 is all they look at - lots of chatter in this subreddit about what numbers to look at). If your T4 is "in range," most docs won't want to touch anything until your thyroid starts to fail. HOWEVER, there is where TSH comes into play. If your TSH is high even with good T4, then how my doc explained it is your thyroid is working really, really hard to produce the hormones that it is. And typically, once the antibodies are discovered, there is no way of knowing how long it's been happening or how damaged your thyroid is, even if your other numbers are currently good. Now to confuse matters, your thyroid could fail for other, non Hashimotos reasons, as noted elsewhere in the thread. Hence, some people have hypothyroidism but not Hashi's, and vice versa if you have the antibodies but your thyroid is still functioning. Now to really complicate things (and where big arguments come into play) - immunomodulatory/immunosuppressant meds are pretty hard core and very powerful. They have serious side effects and can prevent the body from adequately responding to various factors and even worsen other autoimmune diseases. The "treatment" for Hashis is replacement thyroid hormones, which when at the right level etc, have basically no side effects. And taking those immunosuppressant meds won't restore thyroid function - you have antibodies, there is some unknown damage, and there is no way of "healing" your thyroid. The math is very much on the side of "take the tiny cheap replacement hormone." Research is mixed on what approach is any can slow the body's attack of the thyroid (lots of claims about various diets or other approaches), but things that are clear like other autoimmune diseases - high genetic component, monitor and watch, unknown what triggers (although typically some type of high stress/long illness correlates), once the body turns on itself, there's not much that can be done. Upside is that levo is basically bio-identical to what the body produces. My PCP put me on levo when my hormones where high, my TSH was high, but my T4 was perfect. I've had to adjust my diet a bit and add supplements, as Hashi's interferes with metabolism of certain nutrients. And I've had to change how I work out (I can't tolerate cardio or any high stress workouts - strength training, pilates, etc are all fine). And now I get maintenance blood draws. But it's not nearly as bad as the other autoimmune diseases floating around my family (we have great little cluster). Thus ends my TED talk. More on reddit.com

You only need a blood test for anti tpo and TSH. When your anti tpo levels are above 35 you have Hashimoto’s More on reddit.com

Initially diagnosed with "being a woman", then diagnosed with "hormones, you'll be fine", then diagnosed with "Yes your thyroid levels aren't great but there's no need to medicate" and finally diagnosed with Hashimoto's after changing my GP to a female who would actually take me seriously More on reddit.com

Having two early miscarriages. Then started levothyroxine and now am 23 weeks pregnant with a healthy boy :) More on reddit.com