Table 2.
Calculation of diagnostic test sensitivity and specificity for serum concentrations of T4, T3, free T4 (fT4), and TSH in 917 cats with untreated hyperthyroidism (divided into 5 quintiles of disease severity based on T4 concentrations), 32 euthyroid cats suspected of having hyperthyroidism but without the disease, and 131 clinically normal cats
| Hormone | Sensitivity (95% CI) | Specificity (95% CI) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Hyperthyroid (917) | Mild (184) | Mild‐to‐Moderate (183) | Moderate (183) | Moderate‐to‐Severe (183) | Severe (184) | Hyperthyroid Suspect (32) | Clinically Normal (131) | All Euthyroid Cats (163) | |
| Serum T4 | 95.2% (93.4–96.5%) | 76.1% (69.3–82.1) | 100% (97.9–100) | 100% (97.9–100) | 100% (97.9–100) | 100% (97.9–100) | 87.5% (71.0–96.4) | 98.5% (94.6–99.8) | 96.3% (92.2–98.6) |
| Serum T3 | 65.3% (62.1–68.4%) | 20.7% (15.1–27.2) | 38.3% (31.2–45.7) | 75.40% (69.1–81.5) | 92.4% (87.5–95.8) | 100% (98.0–100) | 96.9% (83.7–99.5) | 98.5% (94.6–99.8) | 98.2% (94.7–99.6%) |
| Serum fT4 | 96.8% (95.5–97.9%) | 85.3% (79.4–90.1) | 98.9% (96.1–99.8) | 100% (98.0–100) | 100% (98.0–100) | 100% (98.0–100) | 84.4% (67.2–94.6) | 97.7% (93.4–99.5) | 95.1% (90.6–97.9) |
| Serum TSH | 98.0% (96.9–98.8) | 94.6% (90.2–97.4) | 97.8% (94.5–99.4) | 98.4% (95.3–99.6) | 99.5% (97.0–99.9) | 100% (98.0–100) | 84.4% (67.2–94.6) | 66.4% (57.6–74.4) | 69.9% (62.3–76.9) |
| T4 + fT4 | 93.2% (91.4–94.8) | 67.9% (30.7–74.6) | 98.9% (96.1–99.8) | 99.5% (98.0–100) | 100% (98.0–100) | 100% (98.0–100) | 93.8% (79.2–99.1) | 99.2% (95.8 + 99.9) | 98.2% (94.7–99.6) |
| T4 + TSH | 93.4% (91.5–94.9) | 71.2% (64.1–77.6) | 97.8% (94.5–99.4) | 98.4% (95.3–99.6) | 99.5% (97.0–99.9) | 100% (98.0–100) | 96.9% (83.7–99.5) | 100% (97.2–100) | 99.4% (96.6–99.9) |
| T3 + TSH | 65.1% (61.9–68.2) | 20.7% (15.1–27.2) | 38.3% (31.2–45.7) | 74.9% (67.9–81.0) | 91.8% (86.8–95.3) | 100% (98.0–100) | 96.9% (83.7–99.5) | 99.2% (95.8–99.9) | 98.8% (95.6–99.8) |
| fT4 + TSH | 95.4% (93.9–96.7) | 82.6% (76.3–87.8) | 96.7% (93.0–98.8) | 98.4% (95.3–99.6) | 99.5% (97.0–99.9) | 100% (98.0–100) | 100% (89.0–100) | 99.2% (95.8–99.9) | 99.4% (96.6–99.9) |
| (T4 or fT4) + TSH | 97.0% (95.6–98.0) | 89.1% (83.7–93.2) | 97.8% (94.5–99.4) | 98.4% (95.3–99.6) | 99.5% (97.0–99.9) | 100% (98.0–100) | 96.9% (83.7–99.5) | 99.2% (95.8–99.9) | 98.8% (95.6–99.8) |
95% CI = 95% confidence intervals.