People with a TSH of 3.5 are told online that they are hypothyroid. People with a TSH of 8 and positive antibodies are told to come back next year. Both are wrong, and the reason is almost nobody tests the four things that settle it. This works out which pattern your numbers actually describe, whether it is autoimmune, and what the guidelines say about who gets treated.
TSH alone is not enough to classify anything, which is why most people leave a consultation none the wiser. Enter whatever you have. Units matter here more than almost anywhere, so check your report rather than assuming.
Ranges genuinely differ between laboratories, often between 4.0 and 5.5 at the top. If yours differs from 0.45 to 4.5, entering it changes where the boundaries fall.
Not sure which thyroid markers to ask for yet? Start with the Blood Test Selector.
Possibly not. Reference ranges differ between laboratories, TSH rises naturally with age, and a single raised reading is not a diagnosis under any guideline. What changes the answer is whether free T4 is normal, whether antibodies are positive, and whether the result repeats.
They tell you the direction of travel. Antibody-positive roughly doubles the risk of progressing to overt hypothyroidism, which is why the same TSH is treated differently depending on antibody status. It is one cheap test and it is almost never in a standard package.
If you are in a calorie deficit, that is almost certainly adaptation rather than disease. Free T3 falls when energy intake falls, and it is supposed to. Thyroid hormone does not fix it and taking it suppresses your own production.
Not without a demonstrated deficiency. Iodine and kelp are marketed as thyroid support, and high intake actually raises the risk of progression in autoimmune thyroid disease rather than lowering it.
No. It explains how the decision is made, including the weight-based arithmetic doctors use, so your conversation with a doctor starts in the right place. Levothyroxine is prescription-only and the dose is theirs to set.
