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Functional Lab Ranges for Thyroid Markers-Pathological Range VS Functional Range Your Thyroid Levels May be “Normal” but are they OPTIMAL?

There are two main types of ranges in the field of blood chemistry analysis: a pathological range and a functional range. The pathological range is used to diagnose disease; the functional range is used to assess risk for disease before the disease develops. The references that are provided with laboratory test results are referred to as “the pathological range,” because if the test results are out of range, it usually indicates pathology or disease.

The main difference between the functional range and the pathological range is the degree of deviation allowed within their normal ranges. For example the functional range for TSH may be 1.8– 3.0, but the pathological range may be .5-5.0.

Levels above the pathological range may indicate Hypothyroidism.

Levels above the functional range, but before they reach the extremes of the pathological range, may indicate developing Hypothyroidism. If this seems to confusing, understand that if your levels are in the functional high range you are most likely in the process of developing disease. Sometimes people who suffer with fatigue, brain fog, weight gain, anxiety, trembling, hair loss are told everything is “normal”, because their blood tests are not in the abnormally high or abnormal low levels yet.


Most health care providers within the allopathic medical field believe that care should only be provided when disease is present. This view is generally formed from conventional medical training which ignores the philosophies of preventative medicine and nutrition. Traditional medical training teaches physicians to evaluate blood chemistry in comparison to ranges that determine pathology. If pathology is not present, the patient is considered “healthy.” Again, this kind of mentality and philosophy is what has created the health care crisis we now face.

The main difference between health care providers who embrace or reject functional ranges basically boils down to the definition of health. Some healthcare providers define “health” as the absence of disease, and therefore if you are not diseased then you must be “healthy.” Other healthcare providers such as myself (functional Medicine) define “health” as being free of disease but also having adequate energy levels, healthy digestion, good quality of sleep, balanced emotions, hormones and mood, good memory and focus.


Grab your Thyroid Blood tests and compare your levels to the Functional or Optimal Thyroid ranges

Name of Marker OPTIMAL Range-“Functional Range
TSH 1.8 to 3.0
Total T4 or TT4 6-12 ug/d
Total T3 or TT3 100-180 ng/dL
Free T4 or FT4 1.0 – 1.53 ng/dL
Reverse T3 25-30 ng/dL
Free T3 or FT3 3-4 pg/mL
Thyroxine Binding Globulin or TBG 18 -27 ug/mL
TPO Antibody (auto-antibodies) <15           (best is closest to 0)


Understanding what these Thyroid Bio Markers Mean

  1. – The TSH gives me an idea of how the pituitary is responding to serum levels of Thyroid hormone. The pituitary has different deiodinases than the rest of the body so it can’t be used a marker for tissue levels of thyroid hormone, but it can be helpful if elevated. Why TSH alone is not reliable
  2. Free T3 – How much active thyroid hormone is floating around in the blood. This can be artificially elevated if reverse T3 is high.
  3. Free T4 – This gives me an idea of what kind of thyroid “store” your body has. Remember that not all T4 will turn into T3 and in the presence of inflammation, leptin resistance or nutrient deficiencies your body may turn T4 into Reverse T3.
  4. Reverse T3 – This gives me an idea of what kind of stress the body is under, how much inflammation is going on, and what nutrient deficiencies the patient may be experiencing. High levels of reverse T3 are associated with Thyroid resistance and tissue level hypothyroidism.
  5. Thyroid peroxidase and thyroglobulin antibodies – High antibodies are associated with thyroiditis and autoimmunity. If elevated treatment should be targeted at uncovering your autoimmune Triggers. and balancing your immune system.

Calculate your T3/Reverse ratio and learn why it’s more important than TSH alone-

How To Calculate Your T3 Reverse T3 Ratio- Calculator


Order A Complete Thyroid Testing Panel BELOW. Learn why a TSH and Free T4 is not Enough.

All testing comes with a 15-30 minute consult with Dr Hagmeyer or one of his associate and a Free guide that explain in more detail the pattern of thyroid disease you have.