Your Total T4 Level

What Causes Abnormal Total T4 Levels?

Abnormal total T4 levels can have various causes, ranging in severity from 'troubling' to 'life-threatening'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose abnormal total T4 levels, we could:
  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "abnormal total T4 levels" as a symptom.  Here are eight of many possibilities (more below):
  • Hypopituitarism
  • Autoimmune Tendency
  • Iodine Need
  • Fluorosis*
  • Megaloblastic Anemia
  • Hyperthyroidism
  • Cirrhosis Of The Liver
  • Copper Deficiency
* symptoms can be very similar

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
low TSH
having trouble concentrating
history of folic acid deficiency
poor tolerance of heat
nausea for 1-3 months
some tooth staining or pitting
severe fatigue after slight exertion
cysts in breasts
angry/hostile disposition
loss of appetite
bulging eyes from hyperthyroidism
... and more than 60 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of abnormal total T4 levels:
Cause Probability Status
Copper Deficiency 99% Confirm
Hyperthyroidism 17% Unlikely
Fluorosis** 28% Unlikely
Cirrhosis Of The Liver 5% Ruled out
Megaloblastic Anemia 3% Ruled out
Hypopituitarism 3% Ruled out
Iodine Need 3% Ruled out
Autoimmune Tendency 0% Ruled out
* This is a simple example to illustrate the process
** Symptoms can be very similar

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

If you indicate having had recent lab tests, The Analyst™ will ask further questions including this one:
T4 (Total). Unit: ug/dL [nmol/L]
Possible responses:
→ Don't know
→ Under 4.5 [58] (low)
→ 4.5 to 5.9 [58-76] (low - normal)
→ 6.0 to 11.5 [77-148] (normal)
→ Over 11.5 [148] (elevated)
Based on your response to this question, which may indicate having low TT4 level, having low-normal TT4 level, having normal TT4 level or having elevated TT4 level, The Analyst™ will consider possibilities such as:

When TSH and Total T4 are both low, a poorly-functioning pituitary gland is suspected.


Hypothyroidism also suggests the following possibilities:

Copper Deficiency

There are a limited number of studies that suggest low copper levels may reduce thyroid function.  In cases where hypothyroidism is not responding properly to medication, make sure that copper levels are normal.

Fluoride Toxicity

Though apparently vague and non-specific, most of the symptoms of fluoride toxicity point towards some kind of profound metabolic dysfunction, and are strikingly similar to the symptoms of hypothyroidism.

Iodine Requirement

Low iodine intake can cause hypothyroidism in adults.

Megaloblastic Anemia / Pernicious Anemia

Pernicious anemia is associated with other autoimmune conditions such as Hashimoto's disease, a form of hypothyroidism.

Progesterone Low or Estrogen Dominance

Progesterone increases sensitivity of estrogen receptors, and can therefore redirect estrogen activity and inhibit many of unopposed estrogen's undesirable side-effects, which includes interference with thyroid hormone activity.