Thyroid Function Tests

Endocrine

TSH, FT4, FT3 — primary vs secondary disorders.
TSHFT4FT3

Low TSH, high FT4 (primary hyperthyroid)

Common causes

  • Graves
  • Toxic nodule
  • Thyroiditis
  • Amiodarone

Significance: Confirm with TRAb / uptake scan.

Differential diagnosis

  • Graves
  • Toxic MNG
  • Subacute thyroiditis

Next investigations

  • TRAb
  • Uptake scan
  • USG thyroid

Red flags

  • Thyroid storm: fever, tachy, AF, agitation

Educational support only — not a substitute for clinical judgment.

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WardRound

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