Safe Harbor assist

De-identification: assist, never certification

Pattern-based scrubbing assists Safe Harbor de-identification; it does not certify it. Names without titles or labels, nicknames, unusual date formats, and rare identifiers can survive. Review the output - especially low-confidence spans - before text leaves the clinical context.

Scope

Detection targets the 18 identifier categories of the HIPAA Safe Harbor method (45 CFR 164.514(b)(2)), per HHS OCR guidance. Dates default to year-only handling (the year is permitted; other elements removed); redact mode removes years too. Known names supplied by the caller are always redacted at high confidence.

Uncertainty is surfaced, not hidden

Every detection carries a confidence level. High-confidence spans replace with typed numbered placeholders ([NAME-1], [MRN-1], ...).
Low-confidence spans (heuristic names, biometric wording) are listed for human review with surrounding context.
A residual-risk statement ships inside every result.

Numbers, scoped honestly

On our fully synthetic annotated corpus (9 notes, 49 gold spans across 18 categories): micro recall 95.9%, precision 100%. Known hard misses are kept deliberately in the corpus - bare names after section headings, letter-prefixed reference codes - because they are why the residual-risk statement exists. These numbers describe that corpus, not your charts.

A second layer behind the first

The PHI egress guard independently screens network-tool arguments for high-confidence identifier patterns and denies the call in default mode, regardless of what any scrubber produced. Local tools make zero network calls; lookups send terms and codes only to nine allowlisted hosts.

Honest limits

Regex detection fails silently in the dangerous direction - hence review flows, not trust claims.
No images, audio, waveforms, or free-text addresses beyond street-pattern detection.
Not an Expert Determination substitute; organizations needing certified de-identification need that process.

Corpus, scoring functions, and CI floors: eval/corpus, src/lib/evaluate.ts, tests/eval.spec.ts. Regenerate: pnpm eval.