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Hormones & Fertilitypmol/L

Free T4 (Thyroxine)

Free T4 is the primary hormone produced by the thyroid gland, circulating unbound for conversion into active T3 as tissues require.

Common laboratory aliases and abbreviations:FT4T4 libreThyroxine libreFree T4Free thyroxineT4 libre sérica

Test your personal value

Enter the number from your lab report to instantly see how it compares to reference ranges.

pmol/L
16.75pmol/L
11.5
22
‹ LowRange: 11.5 – 22 pmol/LHigh ›

Physiological Reference Ranges

The ranges below represent standard adult physiological values. Your laboratory's printed reference range always takes precedence.

Adults (general)

11.5 – 22 pmol/L

Adult females

11.5 – 22 pmol/L

Adult males

11.5 – 22 pmol/L

Common alternative units:
ng/dL(×12.87 pmol/L)
pg/mL(×0.1287 pmol/L)

What does a low result mean?

A slightly low free T4 may accompany protracted tiredness, lower dietary iodine, or selenium availability.

What does a high result mean?

A slightly elevated free T4 may indicate transient metabolic shifts or a thyroid hormone dose ready for gentle fine-tuning.

Questions ready for your doctor

Bring these questions to your next consultation to discuss with your healthcare practitioner:

  • Does this free T4 level confirm healthy hormone synthesis?
  • Does any current thyroid medication dosage need slight tailoring?
  • Should we schedule a follow-up assessment in two months?

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Important information — Medical notice

ScanMyLab is for informational purposes only. It does not provide a diagnosis and never replaces the advice of your doctor or laboratory.