Matching RulesMultiple Births

Multiple Births

Specification v3.4.0, section III.C.7

Twins share every Household-tier field by definition, plus an exact Date of Birth — the strongest field in Table B. First Name is the only field doing individuating work in these cases. Four operational refinements:

  • 1. Exact match required when DOB is shared. Whenever Household-tier matching resolves to more than one candidate sharing an identical DOB, First Name comparison SHALL be exact, not fuzzy — the normal one-edit tolerance could otherwise conflate two genuinely different but similar names (e.g., Jayden and Jaden).
  • 2. Fail closed on placeholder or identical first names. Newborn/NICU records routinely use placeholders ("Baby Boy Smith," "Twin A") before a birth certificate name is assigned. Per §V.D, placeholders must be removed prior to matching; if removal leaves no discriminating value, or the first names are genuinely identical, the query SHALL produce more than one candidate and SHALL NOT resolve to a unique match — routing into the base document's existing two-candidate escalation path (§III.B), not a new mechanism.
  • 3. Middle name as a last-resort tiebreaker only, reintroduced specifically within the two-candidate escalation flow when First Name is also tied.
  • 4. Anchor to a persistent identifier after first resolution (MRN, EMPI, FHIR Patient.id — Rule 26, ≈0 collision), so subsequent queries don't re-run the name-based tiebreak every encounter.

Out of scope note: this proposal does not provide a positive matching path for a newborn whose only individual-tier fields are placeholders (no legal name, no non-placeholder DOB distinct from the admission date). Rule 2 above fails such a query closed, correctly, but that leaves the newborn unmatchable under this proposal alone. Below we define a newborn-matching rule via maternal linkage (matching the newborn to an already-verified maternal identity plus a birth-encounter identifier) that is intended to close exactly this gap; this proposal defers newborn matching to that rule rather than duplicating it.

Was this page helpful?