Biochemical Stratification of Patient Studies and Findings (1–6,12,13)
| Free T3 (2–7 pmol/L*) | Free T4 (12–30 pmol/L*) | Thyroid-stimulating hormone (0.45–4.5 μIU/mL*) | Biochemical status | 99mTc uptake (%) | Comment on uptake reference range |
|---|---|---|---|---|---|
| High | High | Low | Hyperthyroidism | >4.5 | 0% FN rate |
| Normal | Normal | Low | Subclinical hyperthyroidism | <4.5 including <0.45 or absent | 0% TP, comprised FN or FP hypothyroidism |
| High | Normal | Low | T3 toxicosis | >4.5 or <0.45 | FP hypothyroidism |
| Normal | High | Low | Thyroiditis | No cases | |
| Low | Low | Low | Secondary hypothyroidism | No cases | |
| Normal | Normal | High | Subclinical hypothyroidism | >0.45 but <4.5 | 100% FN |
| Low or normal | Low | High | Primary hypothyroidism | >0.45 and in over 50% of cases >4.5 | 100% FN |
| Normal | Normal | Normal | Euthyroid | <4.5% | 9% FP rate (6% hyperthyroid, 3% hypothyroid) |
* Reference range.