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T4 Total

Alternative Name:


Clinical Utility:

“thyroxine (T4) is used along with T3 to assess thyroid function. Produced by the thyroid gland, its regulation is controlled by a complex feedback mechanism. Decreasing levels of T4 causes increased production of TSH and TRH by the hypothalamus and pituitary respectively. Therefore, there is an inverse relationship between the Total T4 level and TSH in a patient with an intact thyroid and a normally functioning pituitary axis “


1 mL SST Tube

Collection Instructions:

Fill tube, invert gently 5 times, label with patient name, let stand for minimum of 30 minutes, maximum of 1 hr, spin for 10-15 minutes

Storage Instruction:


Turnaround Time:

1 days

CPT Code:

84436 (1)