An audit log is the sign-in sheet for patient data: an immutable record of who accessed which Protected Health Information (PHI), when, from where, and what they did with it. The HIPAA Security Rule requires audit controls explicitly at 45 CFR §164.312(b), and in real-world investigations — a clinician snooping on a celebrity's record, a breached account exfiltrating data, an Office for Civil Rights (OCR) inquiry — cases are won or lost on whether the logs are complete and trustworthy enough to reconstruct exactly what happened.
For a telemedicine product, "what happened" spans more surfaces than a typical web app. It includes who joined a video session, who viewed or downloaded a recording, who exported records, and which admin changed which permission. Each of those events needs a tamper-evident entry tied to a real, authenticated identity — not a shared service account that makes individual accountability impossible.
Two design consequences follow. First, the logs themselves contain PHI (or enough metadata to be sensitive), so they inherit the same encryption, retention, and access-control requirements as the data they describe, and access to the audit trail must itself be restricted and logged. Second, audit logging must be designed in from day one, because you cannot retroactively log the past — an event you failed to capture is simply gone when an investigation arrives. The common pitfall is bolting on logging late and discovering critical actions (recording access, bulk exports, permission changes) were never recorded, leaving a blind spot exactly where regulators and incident responders look first.
