GT1-5 in HL7 v2: A Field Guide to Guarantor Address
Statements, collection letters, and past-due notices all go where GT1-5 says they go — and when it is left blank or copy-pasted from the patient address, real accounts end up mailing bills to the wrong door.
GT1-5 is the Guarantor Address field, holding the street, city, state, and postal code where billing correspondence should be sent for the responsible party. It is a component field and does not have to match the patient's home address in PID.
What this field contains
Example
GT1-5 carries a full mailing address for the guarantor — here a synthetic Denver address used purely as an example.
Where this trips people up
It is common for test data generators to leave GT1-5 empty and let the billing system silently fall back to the patient address, which masks a real production scenario: a guarantor with a different mailing address, including out-of-state guarantors or PO boxes. Testing only the fallback path means the actual address-population logic, and any validation around malformed or incomplete addresses, never runs until real statements start bouncing.