Table 2.
Median (IQR) serum concentrations of T4, T3, fT4, and TSH in 462 cats with untreated hyperthyroidism (divided into 3 quantiles of disease severity based on T4 concentrations)
| Cat Group | Serum T4 (μg/dL) | Serum T3 (ng/dL) | Serum fT4 (pmol/L) | Serum TSH (ng/mL) |
|---|---|---|---|---|
| Hyperthyroid (462) | 8.7 (6.5–12.9) | 139 (89–224) | 80 (68–100) | <0.03 (<0.03–<0.03) |
| Mild (154) | 5.7 (4.8–6.5) | 76 (59–90) | 64 (57–69) | <0.03 (<0.03–<0.03) |
| Moderate (154) | 8.7 (7.8–10.0) | 141 (123–167) | 81 (78–94) | <0.03 (<0.03–<0.03) |
| Severe (154) | 16.6 (12.9–20.9) | 284 (232–372) | 100 (100–100) | <0.03 (<0.03–<0.03) |
| Clinically normal (131) | 2.1 (1.7–2.6) | 49 (40–60) | 32 (26–38) | 0.04 (<0.03–0.07) |
Reference intervals: T4 = 0.9–3.8 μg/dL; T3 = 35–120 ng/dL; fT4 = 10–51 pmol/L; and cTSH = <0.03–0.3 ng/mL.