Thyroid Blood Tests For Hyperthyroidism and Graves Disease

Published May 25 2012

Just about everyone who is diagnosed with hyperthyroidism and Graves’ Disease receives certain blood tests which help to come up with this diagnosis.  The goal of this article is to discuss some of the common blood tests people with hyperthyroid conditions receive, as well as some of the other tests which can help with the diagnosis.  I’m also going to list the general reference ranges, although keep in mind that different labs will have different reference ranges.

TSH Test (0.4 to 4.5 mIU/L). Many doctors rely on this test for the diagnosis of hyperthyroidism and hypothyroidism.  Just keep in mind that this is a pituitary hormone.  There is still a lot of uncertainty regarding the reference ranges of this test.  In the past the standard reference range was 0.5 to 5.0, and some labs and doctors will still use these reference ranges.  Many labs are beginning to use lower reference ranges (0.3 to 3.0), and this is the reference range I look at.  Although I definitely look at the TSH levels of my patients, and still continue to monitor my own TSH levels when doing follow up blood tests, I don’t rely on this value alone.

Total T4 (4.5 to 12.5 ug/dL). This is the total amount of thyroxine in the body, and is usually increased in people with hyperthyroidism and Graves’ Disease.  It is not as accurate as measuring the free level of thyroid hormone.

Free T4 Test (0.8 to 1.8 ng/dL). This measures the free form of the hormone, which is more accurate of the body’s thyroid hormone levels.  This test is typically high in people with hyperthyroidism and Graves’ Disease, although it is negative in people with subclinical hyperthyroidism.

Total T3 (76 to 180 ng/dL). This is the total amount of triiodothyronine, and like T4, is usually increased in people with hyperthyroid conditions.

Free T3 Test (2.3 to 4.2 pg/mL). Like free T4, free T3 also measures the free form of the hormone, and is more accurate than measuring the bound levels of this hormone.

T3 Uptake (24 to 39%). This test measures the amount of thyroxine-binding globulin (TBG).  Increased levels are common in hyperthyroidism.

Reverse T3 Test (10 to 32 ng/dL). The RT3 test is more commonly positive in people with hypothyroid conditions.  When the body is under a good deal of stress and therefore needs to conserve energy, it will convert excess T4 in the body to Reverse T3 (RT3) in order to clear out the extra T4. According to some sources, adrenal gland problems can inhibit the conversion of T4 to T3, which produces higher quantities of RT3.  This can also happen when iron is low.

Thyroglobulin (<60 ng/mL). This is a protein produced by the thyroid gland, and is commonly high in hyperthyroid conditions, as well as thyroid cancer.  High levels of this usually is due to inflammation and/or damage to the thyroid gland.

TPO Antibodies (0 to 34 IU/mL). These antibodies confirm the presence of an autoimmune thyroid condition, but it’s not specific for Graves’ Disease.  Thyroid Peroxidase antibodies are positive in most people with Hashimoto’s Thyroiditis.  However, many people with Graves’ Disease also test positive for these antibodies.

TSI Antibodies (<140 IU/mL). Thyroid-Stimulating Immunoglobulins are TSH receptor antibodies which are positive in most people (about 70 to 75%) with Graves’ Disease.  However, it is important to understand that just because someone doesn’t test positive for these blood tests don’t mean that they are negative for Graves’ Disease.  There are two other types of TSH receptor antibodies, but this is the main one that I recommend for my patients with hyperthyroidism to get tested for.

Thyroglobulin Antibodies (0 to 20 IU/mL). Not as common in people with Graves’ Disease.  The presence of autoantibodies to thyroglobulin can lead to the destruction of the thyroid gland, and are more common in people with Hashimoto’s Thyroiditis.

Other Types Of Tests

In addition to the thyroid blood tests listed above, some of the following tests can be used in people with hyperthyroid conditions:

Radioactive Iodine Uptake Test.  (6 hours: 3 – 16%; 24 hours: 8 – 25%). This test involves swallowing a liquid or capsule consisting of a small dosage of radioactive iodine in order to measure the amount of radioactive iodine taken up by the thyroid gland.  This is usually done 6 and 24 hours after swallowing the radioactive iodine.  A high uptake is suggestive of Graves’ Disease, although it’s not conclusive of this condition.  If there is also an uneven distribution of the tracer then this can indicate nodules, or a multinodular goiter.  Many people with hyperthyroidism have asked me whether it is necessary to obtain this test, and even though they use a low dosage of radioactive iodine, in my opinion this test isn’t necessary in most cases.

Adrenal Stress Index Test. This is a saliva-based test which is typically performed by holistic doctors to measure the health of the adrenal glands.  Many people with hyperthyroidism and Graves’ Disease have compromised adrenal glands.  And for those people who are looking to restore their health back to normal through a natural treatment protocol, correcting the adrenal gland problem is essential.  This test measures four different cortisol levels according to the circadian pattern, the DHEA levels, 17-OH Progesterone, and tests for a few other values.

Hair Mineral Analysis Test. Yet another test performed by holistic doctors, as this test measures the mineral content of the hair.  Minerals that are tested include calcium, magnesium, sodium, potassium, iron, copper, selenium, chromium, zinc, phosphorous, as well as heavy metals such as aluminum, mercury, cadmium, and lead.  The hair mineral analysis test does more than just test for minerals, as it can provide important information on one’s metabolic rate, carbohydrate tolerance, adrenal and immune system health, etc.  This test can be very helpful when it comes to modifying one’s diet and/or recommending certain nutritional supplements.

Of course there are many other tests that can be performed, but in addition to the blood tests I figured I would list a few of the other tests most commonly performed by endocrinologists (radioactive iodine uptake test) and holistic doctors (adrenal testing and hair mineral analysis).

While these tests can be very valuable, what you need to understand is that blood tests alone don’t tell the entire story.  While blood tests can be  very valuable, you can’t rely on them alone.  They can provide important information when it comes to the diagnosis of hyperthyroidism and Graves’ Disease, but they don’t tell us anything about the cause of the problem.  This is why I always recommend consulting with a holistic doctor who focuses on endocrine disorders, as they will not only look at many of blood tests I discussed in this article, but will most likely recommend some additional tests to help detect the underlying cause of your hyperthyroid condition.