Health data is not data like any other. The GDPR classifies it as sensitive data under article 9, with reinforced protection that weighs on every processing step, every transfer and every tool you connect to it. And yet. Medical reports, whole patient files, already go through ChatGPT or Claude today. So the real question is not whether to use AI. It is how to do it without ever exposing a patient. Here is what the law says, and the method.
What the GDPR says about health data
The principle is clear. Article 9 prohibits processing health data, save for tightly framed exceptions such as the patient's explicit consent or the needs of care. Send a raw file to a third-party model? That is one more processing step, usually outside that frame. Pseudonymization, defined in article 4.5, does not take the data out of the GDPR, but it sharply cuts exposure and the risk of re-identification.
The reflex: anonymize before the AI
- Pseudonymize the document: identity, national ID, dates, addresses and rare éléments become tokens.
- Use the AI on the masked version, without it seeing a real patient.
- Re-identify the result locally, the key staying with you.
Pseudonymization vs anonymization
Pseudonymization is reversible. Tokens, the key kept on your side, re-identification possible whenever you need it. Anonymization, by contrast, is irreversible: the data never comes back. A file you have to re-read with the real names is therefore pseudonymization, not anonymization. The right word keeps you from misjudging the real risk level.
The limits to know
No detection is perfect. A human review is still needed before you send anything out, especially on a dense document where a single rare mention can be enough to re-identify a person. Scans hide text inside the image: you have to OCR it first, then mask it. And the mapping key? Encrypted, under your control alone.
Safe-Doc does all of this. It pseudonymizes before the AI, keeps the original layout, processes the data in the European Union then purges it, and even rewrites scans through OCR. The full details are on the Safe-Doc for healthcare page.
Test it on a real health document. Reversible pseudonymization. Layout preserved.