Thyroid Labs Flashcards
Where is T4 converted to T3?
Inside the cell
Calcitonin offsets?
Parathyroid
Which generation is the most sensitive TSH assay?
The third generation
TPO-Ab and Tg-Ab seen in?
Hashimotos Thyroiditis
TSH-Ab seen in?
Grave’s dz
Total T4 measures?
Both free and bound T4.
Does Free T4 respond faster or slower than TSH is response to therapy?
Free T4 responds faster. Better indicator of therapy.
Fewer interfering factors as well.
Thyroxine Binding Globulin (TBG)
If there is an excess or deficiency of this protein it alters the measurement of T4 or T3 but not the action or the hormone.
Free T4 index (FTI)
Calculated product of the T3 resin uptake and serum T4.
T3 resin uptake measures?
Unoccupied binding sites on TBG. Not a direct measurement of T3.
Total T3 measurement
Less accurate/useful test.
Thyroglobulin
Protein precursor to thyroid hormones
Levels are low or absent in normal thyroid
Elevated in:
Thyroiditis, graves, Thyroid cancer
Also used as a tumor marker of thyroid tissue
A nodule, along with a LOW TSH is suspicious for?
Cancer
Fluid filled nodule is indicative of?
Benign nodule
Nodules > 1-1.5 cm =?
Fine needle biopsy
