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Thyroid Function Tests

Container: Serum (Gold top)

Sample type: Serum

Test name: Thyroid Function Tests a.k.a. TFT, TSH, Free T4, Free T3

Condition / Indication: Thyroid Function, Autoimmune thyroid disease

Special precautions & notes: First line test is TSH, free T3 and/or free T4 are then performed as necessary. Please state any therapy (e.g. thyroxine, carbimazole, amiodarone, lithium etc.)

Reference range: Note new reference range for FT4 from 10/05/24: TSH: 0.38 -5.33 mU/L, Free T4 8.0 – 18.0 pmol/L, Free T3: 3.8 – 6.0 pmol/L. See document below for Reference Ranges in Children (ages 0-18 years). If replaced with T4 ideally TSH should be in the reference range unless suppression is required e.g. Thyroid cancer. In pregnancy the following ranges apply: 1st trimester TSH 0.05 – 3.70 mU/L, FT4 6.7 – 13.9 pmol/L; 2nd trimester TSH 0.31 – 4.35 mU/L, FT4 5.8 – 12.7 pmol/L, 3rd trimester TSH 0.41 – 5.18 mU/L FT4 6.2 – 12.2 pmol/L.

Container: Serum (Gold top)

Ideal volume (mL): 5 mL

Referred outside NBT for analysis? No

Discipline: Clinical Biochemistry

Section: Automated Laboratory

Turnaround time: 1 day