| Bethesda class | Diagnostic category | Cancer risk |
| I | Nondiagnostic (unsatisfactory) | 5 to 10% |
| II | Benign | 0 to 3% |
| III | Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) | 10 to 30% |
| IV | Follicular neoplasm (or suspicious for follicular neoplasm) | 25 to 40% |
| V | Suspicious for malignancy | 50 to 75% |
| VI | Malignant | 97 to 99% |
