Status values

The 5 possible statuses and the rules that trigger each.

Inferred status follows FHIR’s MedicationRequest.status vocabulary. Five possible values, each with deterministic triggers.

The table

Status	Triggered by	Base confidence
active	recent_dispense (within 90d) OR active_order (MedicationRequest status=active, within 180d) OR self_reported_active	0.75 – 0.95 depending on signals
completed	course_completed — explicit completed status OR effectivePeriod.end in the past	0.85 – 0.95
stopped	order_stopped — MedicationRequest.status = stopped	0.85
cancelled	order_cancelled — MedicationRequest.status = cancelled	0.85
unknown	No classifiable signal, or all data is >365 days stale	0.30 – 0.50

Precedence (when multiple rules fire)

active > completed > prescription_expired > stopped > cancelled > unknown

If both active_order and order_stopped fire on resources that resolve to the same medication (via RxNorm grouping), active wins — the current state trumps historical state.

Confidence adjustments

Base confidence values are modified by:

• Corroboration — multiple active-leaning signals firing for the same medication (e.g., active_order + recent_dispense) can push confidence to ~0.95.
• Missing date — −0.20 penalty
• Missing RxNorm code — −0.05 penalty
• Staleness decay — continuous curve past 90 days. A 6-month-old signal is worth more than a 2-year-old one.

Filtering by status

Pass statuses in the request body to filter the response post-inference:

{
  "resources": [ ... ],
  "statuses": ["active"]
}

The engine still runs on all resources; the filter only trims the output list. Good for “show me just active meds” without re-invoking.

Special cases

Medications with only self-reported data

If a MedicationStatement has reported=true (patient-reported, not clinician-recorded), the self_reported_active rule fires with a lower base confidence. Clinician-recorded statements carry more weight.

Medications with no RxNorm code

Grouping still works on normalized display names, but confidence takes a −0.05 penalty since we can’t confirm we’re looking at the right drug across sources.

Prescriptions that expired without a dispense

If a MedicationRequest is status=active but authored >365 days ago and no MedicationDispense exists, prescription_expired fires and status becomes completed. The order was never actually used.