T3 uptake-994
Test info
- Thyroid function test for the diagnosis of hypothyroidism or hyperthyroidism, used with thyroxine (T4) or equivalent to provide free T4 index, FTI.
- An indirect measure of binding protein, the T3 uptake reflects available binding sites (ie, reflects TBG).
- T3 uptake is not a measurement of serum T3. It should never be used alone; rather, its usual application is use with thyroxine (T4).
This test reflects assessment of thyroxine-binding globulin (TBG) and should not be ordered alone.
Specimen
Biotin supplements may interfere with assay.
It is recommended that patients abstain from any biotin containing supplement for 12 - 24 hours prior to blood draw. Biotin is commonly found in hair, skin and nail supplements and multivitamins.
0.8 (pediatric)
0.3 (pediatric)
Immediatley following collection, mix sample by gently inverting 5 times
- Allow sample to clot for a minimum of 30 minutes
- Spin within two (2) hours of sample collection
Gold serum separator (SST) tube
Lt green plasma separator (PST):
Immediately following collection, mix sample thoroughly by gentle inverting 8 - 10 times to prevent clotting
Red:
- Allow sample to clot
- Spin within two (2) hours of sample collection
- Transfer serum to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum
Lt green plasma separator (PST):
Spin within two (2) hours of sample collection
Ambient (preferred) - 14 days
Refrigerated - 14 days
Frozen - 14 days
Freeze/thaw cycles: stable x3
Performance
Electrochemiluminescence Immunoassay (ECLIA)
Clinical and Interpretive info
An interpretive report will be provided