What Thyroid Tests Do You Need? + Printable Lab Slip

Written by

Thyroid testing can be a point of contention among those in the medical community. Many physicians believe that only a few factors, primarily TSH and T4, must be examined to acquire an adequate understanding of individual thyroid function. In reality, there are many other elements in addition to TSH and T4 that should be examined in order gain a better understanding of individual thyroid health.

Knowing what tests should be administered and understanding why they are beneficial is an excellent way for you to become more thyroid aware during Thyroid Awareness Month.

Getting Familiar with Thyroid Tests

To acquire a truly accurate understanding of your thyroid, testing should include TSH, Free T4, Free T3, Reverse T3, Thyroid Antibodies, SHBG, and Leptin.

Thyroid Stimulating Hormone (TSH)

TSH is released by the pituitary and triggers production of T4 by the thyroid gland. As T4 levels increase, TSH levels decrease and vice versa. This relationship helps keep thyroid hormones balanced.

TSH testing is the most commonly utilized method for assessing thyroid function. Because elevated levels of TSH generally suggest that your thyroid is sluggish and not responding well, many physicians use TSH as the sole method of diagnosing thyroid conditions.

Sadly, this leaves out important thyroid factors such as how much thyroid hormone is contained within body tissue. Therefore, reliance on TSH only can lead to misdiagnosis and poor treatment.

Watch Dr. Holtorf explain the inadequacy of TSH testing.

Free T4 (Thyroxine)

Thyroxine, or T4, is the inactive storage form of thyroid hormone. Measuring T4 is important as it indicates how much thyroid hormone is available to be converted into the active thyroid hormone, T3.

Testing the amount of Free T4 in your blood can also help identify if you are suffering from a thyroid condition.

Hypothyroid patients (reduced thyroid function) generally have lower levels of T4 in their bloodstream while hyperthyroid patients (overactive thyroid function) often show increased levels.

Free T3 (Triiodothyronine)

Perhaps the best mark of thyroid function is Free T3. T3 is converted from the storage thyroid hormone, T4. As the active form of thyroid hormone, T3 has significant control over how your thyroid, and body as a whole, functions.

Without proper levels of T3, your metabolism can become inactive or lethargic resulting in reduced energy levels, mental sluggishness, and difficulty focusing. Alternatively, elevated T3 levels can result in increased heart rate, erratic sweating, and jitteriness.

Decreased T3 levels are primarily caused by hypothyroidism, which reduces thyroid hormone production. Heightened amounts of T3 may suggest hyperthyroidism.

Even though T3 may be the best individual gauge of thyroid function it is important to investigate other factors that may inhibit thyroid functionality.

Reverse T3 (Reverse Triiodothyronine)

Reverse T3, much like active thyroid hormone, is converted from T4. However, the function of Reverse T3 is to inhibit the conversion of T4 into T3.

When working correctly and hormone levels are appropriately maintained, Reverse T3 is used to regulate hormone balance. If Reverse T3 levels are elevated, it could indicate improper T4 conversion resulting in hypothyroidism.

High levels of Reverse T3 can impede thyroid function even if T4, T3, and TSH levels are within “normal” ranges. Therefore, it is critical to assess your Reverse T3 levels if you wish to get an accurate representation of your thyroid function.

Thyroid Antibodies

For those with an autoimmune thyroid disorder such as Hashimoto’s Thyroiditis, thyroid antibodies are a major concern. Fortunately, there is a test for that too! You must assess your antibody levels with a simple blood test.

In many Hashimoto’s cases, TSH, T4, and T3 remain within “normal” ranges even though there is significant thyroid dysfunction. Perhaps the best way to identify thyroid-related autoimmune issues is through testing thyroid antibodies.

There are multiple antibodies that should be tested when analyzing your thyroid including TPOAb (Thyroid Peroxidase Antibody), TGAb (Thyroglobulin Antibody) and TSI (Thyroid-stimulating Immunoglobulins). Elevated levels in these areas may indicate an autoimmune disorder such as Hashimoto’s or Graves’ Disease that could otherwise go unnoticed.

SHBG (Sex Hormone-Binding Globulin)

Hormone transport is a critical component of proper bodily function. Even though estrogen and testosterone (the sex hormones) are the primary substances SHBG is concerned with, it still plays an important role in thyroid function. SHBG is necessary for hormone delivery, which makes it an important test factor for assessing the thyroid.

SHBG directs hormones throughout the body by binding to them, thereby removing their availability or “free” quality, and directing them to the appropriate location. Those who exhibit low SHBG levels frequently suffer from poor thyroid hormone transport, which can result in hypothyroidism.


Because it has a significant impact on metabolic function, hunger, reproduction, and fat regulation, leptin has gained a lot of coverage in recent years. One aspect of leptin function that is frequently overshadowed is its effect on the thyroid.

Improper leptin levels, which is related to the development of leptin resistance, can inhibit hypothalamic function resulting in poor TSH production. In addition to reduced TSH prevalence, leptin resistance has also been associated with poor T4 to T3 conversion and increased levels of Reverse T3.

Leptin resistance is frequently caused by poor dieting practices such as chronic dieting. Properly testing leptin levels can facilitate a diagnosis, which may help you resolve your thyroid dysfunction.

The Task of Testing

Acquiring an accurate assessment of your thyroid is the first step in getting better treatment and achieving greater wellness. If you’ve been suffering from common symptoms of thyroid disease such as sluggishness, weight fluctuations, muscle or joint pain, memory issues, and difficulty regulating body temperature, it may be time to get a thorough thyroid diagnostic.

Click here for a free, downloadable lab slip that indicates the elements necessary for a full thyroid panel.

Take part in thyroid awareness by gaining a better understanding of your thyroid through comprehensive testing!