reidentifying-text

Reidentifying Text

Some workflows need to remove PHI for processing but keep the ability to restore it later under authorization — adjudication, patient recontact, linking results back to a record. That is pseudonymization (reversible), not anonymization (irreversible). OpenMed supports it with deidentify(..., keep_mapping=True) to capture a mapping, and reidentify to restore. Everything runs on-device.

When to use

• You need to re-link redacted output to the original record later.
• You are doing GDPR pseudonymization (Art. 4(5)): identifiers held separately, reversible under controlled conditions.
• A reviewer must spot-check redactions against originals.

Do NOT use reversibility when:

• The goal is HIPAA Safe Harbor anonymization or a true anonymous release — a re-identification mapping defeats anonymization. Use method="remove" and keep no mapping.
• The redacted text leaves your trust boundary and the mapping might travel with it. The mapping is the secret; never co-locate it with the de-identified output.

Install

pip install "openmed[hf]"

Quick start: reversible round-trip

import openmed

note = "Patient John Doe (MRN 00481726) seen on 2024-03-02 by Dr. Alice Smith."

# 1) De-identify AND capture the reversal mapping
deid = openmed.deidentify(
    note,
    method="mask",          # or "replace" for realistic surrogates
    keep_mapping=True,       # <-- required to enable reidentify()
    policy="gdpr_pseudonymization",
)

safe_text = deid.deidentified_text       # ship/process this
mapping   = deid.mapping                  # SECRET: store separately, encrypted

# 2) Later, under authorization, restore the original
restored = openmed.reidentify(safe_text, mapping)
assert restored == note

reidentify(deidentified_text, mapping) performs the inverse substitution. The mapping is a dict[str, str] of redacted → original text, produced only when keep_mapping=True.