How to Keep Your Scanned Medical Documents Private: On-Device Scanning with No Cloud Upload
Free printable blood pressure log (PDF)
Most document scanner apps send your scans to their own cloud. That is fine for receipts and shopping lists. It is not fine for lab reports, prescriptions and discharge summaries. Blood Snap's Document Vault is built the other way around: everything stays on your phone.
On-device scanning
Blood Snap uses the document scanner built into your phone. On iPhone that is Apple VisionKit, on Android it is Google ML Kit. Edge detection, cropping, perspective correction and page ordering all run on the device. There is no server round trip and no account needed to scan.
Text recognition also runs on-device, using Google ML Kit. That is how Blood Snap can offer search inside your documents without ever sending a page anywhere.
On-device storage
Scans are saved as PDFs in the app's private storage. They are not in your photo library, not in a shared folder and not visible to other apps. Only Blood Snap can read them.
Excluded from backups
Blood Snap marks the scanned-documents folder so that:
- Android Auto Backup and device-to-device transfer skip it.
- iPhone and iPad device backups and iCloud skip it.
This is deliberate. It means a lost or stolen phone does not leak your medical documents through a cloud backup, and it means Blood Snap never has a copy of your scans on its servers.
The trade-off is that scanned documents are not restored on a new phone. If you want your own backup, use Share PDF to save a copy to Files, Google Drive, iCloud Drive or email.
What Blood Snap does send
Blood Snap does not send scanned documents to anyone. The only data that leaves your phone is what you choose to share, plus the readings and medicines you sync if you are signed in and on Blood Snap Pro. Optional AI features (snap parsing, medicine label scan, Logging tips translation) send data to Groq only after you tap Allow, and never include scanned documents.
How to check for yourself
- Scan a document in More Health → Documents.
- Turn on airplane mode and open the document. It still loads, because it is local.
- Check your iCloud or Google Drive backup settings. The scanned-documents folder is excluded.
Privacy is a feature, not a slogan. If you have questions about how Blood Snap handles your data, the full privacy policy is at bloodsnap.com/privacy.