FT3 Dialysis/Mass Spec
Free Triiodothyronine (T3)
Triiodothyronine (T3), Free, Dialysis and LC/MS-MS
Direct measurement of FT3 by equilibrium dialysis, high-pressure liquid chromatography, and tandem mass spectrometry (ED-HPLC/MS-MS) provides enhanced accuracy over commonly used analog (automated) methods and is not affected by clinical conditions that impact protein binding capacity. Examples of clinical conditions in which the FT3 by dialysis and MS/MS method may be preferred include congenital absence of thyroxine-binding protein (TBG); pregnancy; administration of oral contraceptives or hormone therapy; administration of atypical antipsychotic medications; malignancy or other critical illnesses.
Serum (preferred) or plasma, frozen
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (sodium heparin) tube
Serum/plasma must be separated from cells within 45 minutes of venipuncture. Send serum/plasma in a plastic transfer tube.
Freeze (preferred) or refrigerate.
Stable at room temperature or refrigerated for five days. Stable frozen for 70 days.