Diagnosis Hypothyroidism: Six Questions to Ask Your Doctor

Doctor answering patient's questions
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When hypothyroidism sets in following a thyroidectomy or after treatment with radioactive iodine (RAI), or if you are diagnosed with an underactive thyroid due to autoimmune Hashimoto's thyroiditis, there will be many important questions to ask your doctor. Here are six of the most common and important ones.

1. What is the normal thyroid-stimulating hormone (TSH) range at your lab?

The TSH test is the most commonly used test for diagnosis and management of hypothyroidism in the United States.

But different labs often have slightly different values for what is known as the "TSH reference range." This measure is the range of test values deemed to reflect a normal population.

At many labs, the TSH reference range runs from 0.5 to 4.5 . A TSH value of less than 0.5 is considered hyperthyroid (overactive thyroid), while a TSH value of more than 4.5 is considered potentially hypothyroid (underactive thyroid). Different labs might use a lower limit of anywhere from 0.35 to 0.6, and an upper threshold of anywhere from 4.0 to 6.0. In any case, it is important for you to be aware of the reference range at the lab where your blood is sent, so you know the standards by which you are being diagnosed.

NOTE: Since late 2002, the American Association of Clinical Endocrinologists (AACE) and other professional groups have gone back and forth regarding recommendations to narrow the TSH range, so 0.3 to 3.0.

But doctors have not come to agreement. So some doctors consider levels below .3 and above 3.0 as evidence of thyroid dysfunction. Others continue to use the old standards, the ones that continue to prevail at most labs. 

2. What TSH level will you use as a target for me?

This is a loaded but important question.

Your physician's answer will reveal her or his philosophy about what represents a "normal" level for TSH. Some doctors believe that getting a patient into the very top of the normal range is the objective of hypothyroidism treatment. For example, using the 4.5 TSH standard, some physicians believe that prescribing thyroid hormone replacement medication to get a patient's TSH down to below 4.5 (even perhaps just down to 4.4) would constitute full treatment. Some physicians actually feel that levels below 10.0 are "subclinical hypothyroidism" and don't warrant treatment.

Physicians vary in what TSH level within the normal range they believe makes an ideal target. Some practitioners, for example, might target a TSH level between 1.0 and 2.0 based on their own experience suggesting that patients may feel best at these levels.

Other doctors closely follow the guidelines discussed earlier, and believe that thyroid hormone replacement treatment should target a TSH level of no more than 3.0 in hypothyroid patients.

3. What medication are you prescribing for me?

Since you probably can't read the handwriting, you'll need to ask! The question here is whether your doctor chooses a brand name or a generic medication.

If a brand name is prescribed, you'll want to know whether your doctor specified "no generic substitutions" or "dispense as written (DAW)." In the United States, brand name thyroid hormone replacement drugs include:

  • Levothyroxine (synthetic thyroxine/T4): Synthroid, Levoxyl, Tirosint, Unithroid, or generic
  • Liothyronine (synthetic triiodothyronine/T3): Cytomel, or generic
  • Desiccated natural thyroid: Armour, Nature-throid, Thyroid WP, or generic NP Thyroid

Most patients are prescribed levothyroxine. Thyroid experts have traditionally warned patients about generic levothyroxine. Because of the potential for variation in potency between brand name drugs and generics and the potential that patients could receive different generic brands when refilling prescriptions, the ATA and AACE have advised that physicians should —

1) Alert patients that their levothyroxine preparation may be switched at the pharmacy
2) Encourage patients to remain on their current levothyroxine preparation when possible
3) Ensure that patients understand if they receive a new levothyroxine preparation that they will need to repeat a thyroid-stimulating hormone (TSH) blood test four to six weeks later to determine if they need further dose adjustment

4. How quickly can we expect relief of symptoms, and optimization of my thyroid blood tests, given the dosage prescribed?

The key question here is whether your doctor is giving you a small dose of thyroid replacement and intends to adjust your levels very slowly, or whether he or she is attempting to get you into the optimal range as fast as possible. There are valid reasons for both approaches, but as a patient it's important to know what to expect.

Some doctors may put you on a very low dose and then tell you that you will feel better in two weeks. If then two weeks come and go and you don't feel better, you might think the drug is not working. But treatments can take quite a while to take effect. 

If you are a senior, or if you have a history of heart problems, physicians will often start you on a very low dose of thyroid hormone replacement in order to gauge your response and to avoid aggravating your heart problem.

5. How often will you run thyroid tests until we get my levels back into the reference range and optimal? 

Ideally, your doctor is going to stay on top of getting you into normal range. For most cases, this probably means seeing you every six to eight weeks for blood tests and then following up with an adjustment to your dosage until you are feeling better and your levels are optimal .

6. After I'm in the optimal range, how often do you suggest I come back for blood tests to make sure my dosage needs haven't changed?

If your doctor says you don't need to come in at least once a year, it is time to start wondering whether you are seeing the right doctor. Most experts recommend that patients get tested at least every six months during the first year or two, followed by once a year thereafter.

A Word From Verywell

There's one additional question that is important to ask: "If I have questions between appointments, how can I get in touch with you? Do you return calls yourself, or do your nurses return calls for you? Do you have an email address for corresponding with patients?"

This question will help you to gauge how available your doctor plans to be. If you have the option of searching out a different physician, your doctor's response to this question may help you to decide what to do. Some doctors will return calls themselves and will even answer email. Others choose to refer all questions to nurses (who may offer equally good or even better information). But if you want personalized, hands-on service, listen closely to what your doctor says here. You'll get an idea of what to expect.


Braverman, L, Cooper D. Werner & Ingbar's The Thyroid, 10th Edition. WLL/Wolters Kluwer; 2012.

Garber, J, Cobin, R, Gharib, H, et. al. "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Endocrine Practice. Vol 18 No. 6 November/December 2012.