Bethesda System (Thyroid Cytopathology)

The Bethesda System for Reporting Thyroid Cytopathology, the standardized six-category scheme a cytopathologist assigns to a thyroid fine-needle-aspiration (FNA), categories I/II/III/IV/V/VI.

Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.

Example

Bethesda thyroid category
IV - follicular neoplasm or suspicious for one

Result: Bethesda category IV: follicular neoplasm or suspicious for a follicular neoplasm.

The tool opens with these values already filled in. Replace them with your own.

What the result means

Category I
Nondiagnostic or unsatisfactory.
Category II
Benign.
Category III
Atypia of undetermined significance (AUS/FLUS).
Category IV
Follicular neoplasm or suspicious for a follicular neoplasm.
Category V
Suspicious for malignancy.
Category VI
Malignant.

What you enter

  • Bethesda thyroid category
How this is calculated

Cibas ES, Ali SZ. The 2017 Bethesda System for Reporting Thyroid Cytopathology. Thyroid. 2017;27(11):1341-1346. Read the source ↗

A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.

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Built by Clay Good. Source on GitHub.