^M01
MFN^M01 — Master File Not Otherwise Specified
MFN^M01 is the generic master file notification message used when a master file is updated and no specific MFN event type (M02-M12) applies. It communicates changes to reference data tables that must be synchronized across systems.
When Is This Sent?
When a generic master file is updated — charge master, procedure catalog, location table — and no specific MFN event type covers the data. Also used as a fallback when the receiving system only supports the generic MFN^M01 rather than specific types.
Real-World Usage
Master file synchronization is a common but often neglected integration requirement. Systems like PACS, LIS, and pharmacy maintain local copies of shared reference data (procedure codes, locations, charge codes). MFN^M01 enables the source-of-truth system to push updates to all dependents. Site-specific Z-segments (ZMF) are frequently used to carry custom master file content not covered by standard HL7 segments.
Message Structure
Segment names link to their field-level reference pages.
| # | Segment | Purpose in this message | Req | Repeat |
|---|---|---|---|---|
| 1 | MSH | Message header with MFN^M01 in MSH.9 | R | — |
| 2 | MFI | Master file identification: file name, application identifier, update mode | R | — |
| 3 | MFE | Master file entry: action code (MAD=add, MDL=delete, MUP=update) and record-level key | R | Yes |
| 4 | ZMF | Site-specific Z-segment carrying custom master file record content | O | Yes |
Example Message
Realistic example with fake patient data. Paste into the HL7 Message Viewer to explore interactively.
1MSH||^~\&|CHARGEMASTER|HOSPITAL_A|BILLING_SYSTEM|HOSPITAL_A|20260310080000||MFN^M01^MFN_M01|MFN00001|P|2.5.1 2MFI||CDM^Charge Description Master^HL70175||UPD|||AL 3MFE||MAD|20260310080000|71046^Chest 2 Views^CPT4 4ZMF||71046|Chest 2 Views|560.00|RAD|ACTIVE
Troubleshooting Scenarios
New procedure codes added to charge master not appearing in downstream system
Cause
MFN^M01 messages are being sent but the receiving system cannot parse the ZMF segment, so the new record data is silently ignored.
Fix
Work with the receiving system vendor to define a standard ZMF segment structure that their parser can handle. Alternatively, use a standard segment (e.g., CDM for charge master) if the receiving system supports the specific MFN event type.
Master file delete (MDL) in MFE removes active records in downstream system
Cause
MFE.1=MDL (delete) is being sent for codes that are being retired at the source but are still referenced by active orders or records in the downstream system.
Fix
Implement a soft-delete pattern — use MFE.1=MUP (update) with an inactive status flag rather than MDL. This preserves the reference data for historical records while preventing use in new transactions.
Common Confusions
MFN^M01 (generic) vs specific MFN types (M02-M12). M01 is the catch-all when no specific type fits. M02 is specifically for staff/practitioner master files; M04 is for charge description master; M05 is for patient location master. Use the specific type when available — it provides semantic clarity and better receiver-side validation. Only use M01 when the data doesn't fit a specific event.
Related Message Types
Segment Reference
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