Thyroid Blood Work: Going beyond TSH and T4

Posted by on Apr 3, 2014 in Autoimmune Conditions, Thyroid | 0 comments

Many patients arrive at my office after years of feeling lousy.  They’ve had their thyroid function checked and have been assured it is normal.  But they feel terrible, experiencing fatigue, depression, brain fog and a host of other symptoms.

The problem starts with the fact that the typical blood work run to test for thyroid disease is incomplete and only provides part of the picture.  TSH and T4 are the most common thyroid tests.  These two alone don’t reveal enough about what is really driving the patient’s symptoms.  To understand the complete picture of thyroid function, more needs to be done.  The danger in waiting until TSH is out of range (either low or high) is that it leads to conditions that are difficult to reverse.  The goal is to address the symptoms before full-blown disease is present.

The following tests will help determine what the underlying cause of the symptoms is:

  • A full thyroid blood panel that includes:  TSH, free T4, free T3. Total T3, Total T4, T3 uptake, Thyroid anti-bodies
  • CMP (Comprehensive Metabolic Panel)
  • Review level of stress

To understand why these tests are all important in determining how your thyroid is truly functioning, we need to do a little biochemistry lesson.

Thyroid Feedback Loop

Let’s start in the brain.

The pituitary gland gets a message from the hypothalamus, located in the brain, that the body needs to activate the thyroid.  The process starts with serotonin and dopamine, which drives the production of TSH (thyroid stimulating hormones) in the pituitary.  Stress affects the level of serotonin and dopamine in the brain so that’s why stress levels are important to know.

TSH travels to the thyroid and tells it to produce T3, about 7% of the thyroid production, and T4, about 93% of the production.  The T3 is the more active form and is available to be used by the cells.

T4 travels to the liver to be converted into useable T3.  From there, it goes to the cells.  Liver function impacts the conversion of T4 to T3, making the liver test important.

From the complete blood work, we can tell if the symptoms are due to a brain, liver or thyroid issue.  So if you are experiencing thyroid-like symptoms, seek the support of a functional medicine clinician who can determine the root cause of your condition.

Checking for thyroid anti-bodies is also critical.  The presence of these indicates an autoimmune reaction that could be representative of an autoimmune disease or the onset of one.  At this point, it is very important to do further screening to fully understand the health of the thyroid.

From the complete blood work, we can tell if the symptoms are due to a brain, liver or thyroid issue.  So if you are experiencing thyroid-like symptoms, seek the support of a functional medicine clinician who can determine the root cause of your condition.

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