thyroid lab checklist

A Quick Guide To Understanding Your Thyroid Labs

Testing thyroid lab values is crucial in understanding the nature of your thyroid function. The most common thyroid lab drawn is TSH (thyroid stimulating hormone). While that test alone gives some information a full thyroid panel is usually needed to get the whole picture. By evaluating symptoms with lab testing you and your doctor can determine if you have an under-active thyroid, overactive thyroid, nutrient deficiency contributing to thyroid dysregulation, and/or an autoimmune thyroid condition. 


Types of Thyroid Testing  


Thyroid bio-markers


Thyroid stimulating hormone (TSH) is the pituitary hormone that acts as a messenger to the thyroid gland. If the pituitary gland detects that there is too little thyroid hormone in the blood, it will produce more TSH, prompting the thyroid gland to produce more thyroid hormone. When the pituitary detects too much thyroid hormone, it slows the production of TSH, signaling the thyroid gland to do the same.


Total T4 and Total T3

These are the initial hormones produced by the thyroid gland. They are the hormones that are “on the bench, essentially next up to bat.” These levels are the total amount of thyroid hormone we have produced but can be bound by proteins making them unable to bind to cells. T4 must also must go through a chemical process called  monodeiodination in which it loses an atom of iodine to become triiodothyronine (T3) the active thyroid hormone.


Free T4 and Free T3

Free T4 and Free T3 are not bound to proteins and are considered the active forms of thyroid hormone in the body. 


Reverse T3

Reverse T3 is a trouble maker. When T4 converts to T3 it can also convert to Reverse T3. Although they have similar names Reverse T3 does nothing but attaches to thyroid receptors, unable to activate them, effectively blocking free T3 from doing its job. 



Thyroglobulin (Tg) is a protein produced by the thyroid gland. It is mostly used a tumor marker to help guide thyroid cancer treatment. The aim of cancer treatment is the eradication of all cancer cells. The elevation of Tg is a sign that cancer cells are still present following thyroid removal surgery (thyroidectomy) or radioactive ablation (RAI) therapy.


Antibody Testing

Thyroid disorders can be caused by autoimmune conditions in which the body mistakes your thyroid as outside invader and attacks it. To evaluate for autoimmunity thyroid antibodies will be tested. The most common autoimmune thyroid condition is Hashimoto’s thyroiditis. The three antibody tests include: Thyroid Peroxidase antibodies (TPO), Thyroglobulin antibodies (TG), and Thyroid stimulating hormone receptor antibodies (TRAB). Contrary to belief, any and/or all of these antibodies can be elevated in autoimmune hypothyroid (Hasimotos), autoimmune hyperthyroid (Graves), and thyroid cancer. 


Thyroid Binding Proteins 

Thyroid Binding Globulin (TBG) measures a protein called globulin that is responsible for carrying around T4 and T3 through the blood stream. Having abnormal binding globulin effects how the thyroid hormones interact with cell receptors, helping to explain why thyroid symptoms develop in people with otherwise normally functioning glands.


Nutrient Testing 

Thyroid production and optimal conversion is largely dependent on nutrient cofactors that can easily be tested in serum samples or urine.  It’s important to test for adequate ferritin, selenium, zinc, iodine, Vitamin D and Vitamin A.


Thyroid Disorder Symptoms 

Producing too much thyroid and too little thyroid hormone will have opposite effects on the body. The thyroid is considered the ringleader of the body, it really does control the body’s entire metabolism. If you are experiencing any of the associated symptoms below its time to get your labs tested!


Hypothyroid Symptoms

Hyperthyroid Symptoms

  • Weight gain
  • Fatigue
  • Depression
  • Dry skin
  • Brain fog
  • Cold intolerance
  • Muscle cramps
  • Hair loss
  • Constipation
  • Weight loss
  • Heart palpitations
  • Fatigue
  • Agitation
  • Insomnia
  • Heat intolerance
  • Shaking hands
  • Diarrhea
  • Increased appetite
  • Thinning hair
  • Shortness of breath
  • High blood pressure




Dr. Erin Winter

Naturopathic Doctor Flagstaff

Winter Wellness


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