Table 3.
Conditions Associated with Hyperthyroxinemia
| Thyroid Function Tests | ||||||
|---|---|---|---|---|---|---|
| Defect | T4 | T3 | rT3 | TSH | FT4 direct | FT4 dialysis |
| ↑TBG | ↑ | ↑ | ↑ | N | N | N |
| ↑TTR* | ↑ | N | ↑ | N | N | N |
| FDH | ↑ | ↑ or N | ↑ | N | ↑ | N |
| RTH β** | ↑ | ↑ or N | ↑ | sl↑ or N | ↑ | ↑ |
| SBP2 | ↑ | ↓ | ↑ | sl↑ or N | ↑ | ↑ |
| Acute NTI | ↑ | ↓↓ | ↑ | N | ↑ or N | N |
*
Refers to TTR with increased affinity for T4 and rT3
**
Includes nonTR-RTH
TBG, T4 binding globulin; TTR, transthyretin;
FDH, familial dysalbuminemic hyperthyroxinemia;
SBP2, selenocysteine insertion binding sequence protein;
NTI, nonthyroidal illness;
sl, slight; ↑, increased; ↓, decreased; N, normal.