FrT3 (FREE TRIIODOTHYRONINE)

Description

  • 1.7 -4.20 pg/ml

Clinical significance

  • Whenever the thyroid function tests i.e., T3, T4, TSH fails to give a diagnostic conclusion, a combination of FT4 and FT3 is checked. Free T3 concentration, which represents about 0.3% of the total circulating hormone concentration, is maintained independently of changes of binding protein levels
  • Determination of free T3 concentration is a true measure of Thyroid status and cellular metabolism. Assessment of free T3 is of interest in some cases of T3 thyrotoxicosis when free T4 and TSH may be within normal range. Patients who are on treatment with derailed HPT axis, estimation of FT3 along with FT4 facilitates the diagnosis

When to get tested

  • When there is s/s of Hyperthyroidism (Increased heart rate, Anxiety, weight loss, difficulty sleeping, tremors in the hands, weakness, and menstrual irregularity)

Elevated level

  • T3 Thyrotoxicosis when FrT4 and TSH levels are within normal limits
  • Hyperthyroidism
  • Patients inadequately treated with ATD

Decreased level

  • Hypothyroidism
  • Inadequately treated hypothyroidism
  • Euthyroid sick syndrome
  • Low T3 syndrome

Profile

ALL TEST

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