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Date of last update: 10/17/2017.

Forum Name: Endocrinology Topics

Question: TSH Normal, fT4 Normal, fT3 HIGH but with HYPOthyroid sympts

 Meggles89 - Tue Jul 06, 2010 12:37 pm

TSH in May of 2009 was 3.9
TSH in July of 2010 is 2.33
Free T4 in July of 2010 is 0.84 (Ref 0.40-1.40 ng/dl)
Free T3 in July of 2010 is 4.5 H (Ref 2.5-3.9 pg/mL)

Shouldn't my TSH and fT4 reflect the elevated fT3? I feel really bad; joint pain, fatigue, muscle twitches and aches, constipation, gray hair, continuous cold sores, minute weight gain, and LOW libido. All of this has compiled over 2.5 years. I used to be a vibrant, active young woman. I used to snowboard and play sports, but now I am too tired and achey to do anything. My current doctor recommended that I see a therapist because my test results are "normal"....but I don't feel depressed (I've always been "bubbly" and optimistic), I feel like I have purpose in life I'm just too tired to do anything.

(Just some family background: Paternal Grandfather had RA, Diabetes, and many cardiovascular ailments, he passed from squamous cell carcinoma of the Lungs. Paternal Grandmother has RA, Hashimoto's,Heart Disease, and breast cancer survivor. My Father has RA and Addison's. My Aunt on my father's side has Hashimoto's. Maternal Grandmother has Diabetes, RA, and Grave's. Maternal Grandfather I don't know much about. My mother and her sisters all suffer from Grave's/Hashimoto's. Up until now, I have been the healthiest member of this family.)

 Dr.M.Aroon kamath - Sun Jul 18, 2010 1:05 am

User avatar Hi,
In the blood, thyroid hormones exist in two forms- T4 and T3. T3 is the active form. T3 is primarily synthesized by monodeiodiation of T4 in the peripheral tissues(chiefly in the liver and kidneys) rather than by direct secretion by the thyroid gland. Physical, mental and environmental stresses can inhibit the deiodinating enzyme, causing less T4 to be converted to T3, and thereby decreasing the amount of active thyroid hormone available to the cells. Besides, more T4 is gets shunted towards production of rT3(a bioloigically inactive form of T3) causing an elevation in rT3.

Total Free T3(FT3) measurement measures T3 and rT3 combined. Therefore, if an rT3 elevation is suspected, a measurement of rT3 must be performed. This is valuable in identifying a condition called "Reverse T3 Dominance".

When a patient produces excessive levels of rT3 they will usually present with hypothyroid symptoms.

Many factors can elevate rT3 levels:
- Chronic illnesses,
- Low protein intake / poor protein digestion,
- High simple carbohydrate intake,
- Starvation diets, fasting,
- Cadmium, mercury and lead toxicity
- Selenium deficiency,
- Potassium and Zinc deficiency,
- High stress levels (especially high cortisol),
- Compromised liver or kidney function.

Therefore, in your case, a possible 'Reverse T3 Dominance' needs to be excluded.Slightly elevated T3 levels may also occur in pregnancy or during estrogen therapy.

Since late 2002, the American Association of Clinical Endocrinologists (AACE) revised the normal range to 0.3-3.0 for serum TSH levels.Prior to 2002, the commonly used range was 0.5-5.0.

Your TSH in July of 2010 was 2.33. Although this falls within the 'normal' range, TSH levels must not be interpreted in isolation.If the TSH levels are even above 2.0, you may need to be treated for hypothyroidism as you are symptomatic.

I hope this information is is helpful.
Best wishes!

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