Clinical Significance

T3 Uptake - Decreased: Pregnancy, estrogens, hyperproteinemia, acute intermittent porphyria.
Increased: Androgens, hyperproteinemia, stress, acute liver disease.
This assay is a measure of available thyroid hormone binding sites and should be interpreted with thyroxine levels.

Preferred Specimen(s)
1 mL serum

Alternative Specimen(s)
Plasma collected in: Sodium heparin (green-top) or lithium heparin (green-top) tube

Minimum Volume
0.5 mL

Transport Container
Serum Separator Tube (SST®)

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 7 days
Refrigerated: 10 days
Frozen: 28 days

Methodology
Immunoassay (IA)

Reference Range(s)
22-35 %

Alternative Name(s)
Resin Uptake,Triiodothyronine, Resin Uptake (T3),T3 Index,T3RU,T3 Resin Uptake,T3 (Triiodothyronine),Hanolsky Uptake Test