General Investigations
1) Thyroid Function Test (TFTs) X
- fT4
- fT3
- TSH
These tests can be abnormal even in some severe non-thyroid diseases, specially ICU patients but then, the patient is clinically euthyroid (sick euthyroid syndrome)
When ordering TFTs, always order free T3 & free T4, not total.
2) Thyroid scan (imaging)
- With radioactive Iodine or technetium
- Radioactive substance is taken up by the gland & pics are taken
- Used to see the “activity” of the gland
- Normal gland: normal uptake pattern
- Hyperactive gland: Increased uptake
- Hypoactive gland: Decreased uptake
3) Ultrasound (imaging): May help to see nodules /cysts in the gland, but cannot differentiate benign from malignant.
4) Fine needle aspiration (needle biopsy)
- Also called FNA biopsy
- Done if there is a nodule (benign or malig)