The review is needed in the suspected diagnosis of hyper- or hypothyroidism.
T4 is the main hormone secreted by the thyroid, the free form is the only active.
Blood Sample EDTA (ethylene diamine tetra-acetic acid).
radioimmunoassay or enzyme immunoassay.
They went in 1-3 days.
from 45 to 110 mcg / L, 60 to 140 mol / L.
(Conversion factors: ug x 1.29 = nmol; nmol x = 0.77 mcg.)
the rate is:
– Increased in hyperthyroidism accompanying low levels of TSH;
– Lowered in hypothyroidism with an elevated TSH.
If hypothalamic-pituitary reached, the TSH is normal.
Beware of medications that can interfere with thyroid function as antithyroid, Lugol, lithium, but also those containing thyroid hormones and iodine.