# Skin-lesion test separates diagnosis accuracy from discharge risk
> CNN led diagnosis; its preset discharge rule missed more melanomas.
By BIGCHANGE.AI Editorial
Published: 2026-10-26T00:16:18.025Z
Updated: 2026-10-26T00:16:18.025Z
Canonical: https://bigchange.ai/blog/skin-lesion-test-diagnosis-discharge-threshold

AI-generated conceptual illustration by BIG CHANGE.
Magnus Lynch's [October 25 test](https://lynchlab.net/llm-skin-cancer) compares diagnosis with discharge recommendations.
## The big change
- **What changed:** Six-label accuracy favored a convolutional neural network (CNN).
- **Why it matters:** Correct labels cannot establish safety of recommendations to stop assessment.
- **What to watch:** The incomplete threshold-matching rule limits discharge comparisons.
## What the numbers measure
First-choice accuracy counts correct diagnoses. A discharge label means no further assessment; no patients were discharged.
Of 200 selected, biopsied lesions (100 keep, 100 discharge; 30 melanomas), CNN labelled 125 correctly; author-labelled GPT-6 Astra and Claude Fable 5.1 scored 84 and 85. Each language model was run once per case; exact revisions and run dates are undisclosed.
At its preset threshold, CNN recommended discharge for 18/30 melanomas; language models, three and four. A threshold change improved CNN's count. BIG CHANGE did not rerun it.
[MILK10k](https://api.isic-archive.com/doi/milk10k/) pairs clinical and dermoscopic images. This cohort cannot establish routine-care performance; public release leaves training exposure unresolved.
## Sources
- [Magnus Lynch skin-cancer comparison](https://lynchlab.net/llm-skin-cancer) — Author protocol; model revisions and run dates undisclosed.
- [MILK10k, ISIC Archive](https://api.isic-archive.com/doi/milk10k/) — Dataset description, paired-image design and image licence; distinct from the author's selected sample.
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