HL7 OM7 Additional Basic Attributes
HL7 field reference OM7 fields from HL7 v2.5.1 Show fields
These are the generated fields for the version selected at the top of the page. The document stays the same, but the reference panel follows that version.
Fields
| Field | Name | Required | Repeatable | Type | Table |
|---|---|---|---|---|---|
| OM7.1 | Sequence Number - Test/Observation Master File | Yes | No | NM | |
| OM7.2 | Universal Service Identifier | Yes | No | CE | |
| OM7.3 | Category Identifier | No | Yes | CE | 0412 |
| OM7.4 | Category Description | No | No | TX | |
| OM7.5 | Category Synonym | No | Yes | ST | |
| OM7.6 | Effective Test/Service Start Date/Time | No | No | TS | |
| OM7.7 | Effective Test/Service End Date/Time | No | No | TS | |
| OM7.8 | Test/Service Default Duration Quantity | No | No | NM | |
| OM7.9 | Test/Service Default Duration Units | No | No | CE | 9999 |
| OM7.10 | Test/Service Default Frequency | No | No | IS | 0335 |
| OM7.11 | Consent Indicator | No | No | ID | 0136 |
| OM7.12 | Consent Identifier | No | No | CE | 0413 |
| OM7.13 | Consent Effective Start Date/Time | No | No | TS | |
| OM7.14 | Consent Effective End Date/Time | No | No | TS | |
| OM7.15 | Consent Interval Quantity | No | No | NM | |
| OM7.16 | Consent Interval Units | No | No | CE | 0414 |
| OM7.17 | Consent Waiting Period Quantity | No | No | NM | |
| OM7.18 | Consent Waiting Period Units | No | No | CE | 0414 |
| OM7.19 | Effective Date/Time of Change | No | No | TS | |
| OM7.20 | Entered By | No | No | XCN | |
| OM7.21 | Orderable-at Location | No | Yes | PL | |
| OM7.22 | Formulary Status | No | No | IS | 0473 |
| OM7.23 | Special Order Indicator | No | No | ID | 0136 |
| OM7.24 | Primary Key Value - CDM | No | Yes | CE | 0132 |
OM7 carries additional service/test attributes such as categorization, consent, departments, and reporting rules.
Master-file segments update reference data rather than describing a single patient event. They define locations, staff, providers, test catalogs, charge items, inventory items, languages, certificates, and other shared records.
Because many downstream messages depend on this data, small changes here can have large effects. Use stable identifiers, effective dates, action codes, and clear ownership rules instead of treating a master-file feed like a loose spreadsheet export.
The v2.5.1 structures show OM7 in MFN_M12 - Master file notification message. That tells you where it can appear, but the implementation guide still decides which optional fields are meaningful.
For practical interface work, read the generated field panel for datatype, required, repeatable, and table details, then use the notes below to decide what the field should mean in the receiving workflow.
OM7-1 identifies the Sequence Number - Test/Observation Master File for this master-file record. Send the identifier that the receiving system actually keys on, and keep the assigning authority or coding system visible when the datatype supports it.
OM7-2 identifies the Universal Service Identifier for this master-file record. Send the identifier that the receiving system actually keys on, and keep the assigning authority or coding system visible when the datatype supports it.
OM7-3 identifies the Category Identifier for this master-file record. Send the identifier that the receiving system actually keys on, and keep the assigning authority or coding system visible when the datatype supports it.
If there are several identifiers, use repetitions deliberately and make each repeat self-explanatory rather than relying on position alone.
OM7-4 is human-readable context. Keep it useful for display and troubleshooting, but do not hide required workflow logic here unless the implementation guide explicitly says the receiver parses it.
OM7-5 qualifies the master-file record rather than identifying it. This is the sort of field receivers often use for branching, filtering, or display grouping.
This field can repeat. Use repetitions for separate real-world values, not as a workaround for putting several unrelated ideas in one field.
OM7-6 is a timing field. Send the real source-system precision, do not pad unknown dates or times, and agree how timezone offsets are handled when time of day matters.
For effective and end dates, make the boundary rule explicit. Receivers need to know whether the value is inclusive, exclusive, planned, actual, or merely informational.
OM7-7 is a timing field. Send the real source-system precision, do not pad unknown dates or times, and agree how timezone offsets are handled when time of day matters.
For effective and end dates, make the boundary rule explicit. Receivers need to know whether the value is inclusive, exclusive, planned, actual, or merely informational.
OM7-8 carries a measured, counted, priced, or dosed value. A number without the expected unit, currency, or companion qualifier is much easier to misread than an empty field.
OM7-9 supplies the units that make the companion numeric field meaningful. Units should be coded consistently, especially for medication, lab, specimen, and billing quantities.
The generated panel links this to HL7 table 9999; many real interfaces narrow that list further, so follow the receiver's implementation guide.
OM7-10 carries Test/Service Default Frequency for this master-file record. Populate it only when the receiver has a clear use for it, and keep the value in the datatype shape shown in the generated field panel.
The generated panel links this to HL7 table 0335; many real interfaces narrow that list further, so follow the receiver's implementation guide.
OM7-11 tells the receiver the state of this master-file record. Status fields often drive workflow branches, so use the agreed code and do not infer a status just because another field looks complete.
The coded value should follow HL7 table 0136 or the narrower table in the local profile.
OM7-12 identifies the Consent Identifier for this master-file record. Send the identifier that the receiving system actually keys on, and keep the assigning authority or coding system visible when the datatype supports it.
The generated panel links this to HL7 table 0413; many real interfaces narrow that list further, so follow the receiver's implementation guide.
OM7-13 is a timing field. Send the real source-system precision, do not pad unknown dates or times, and agree how timezone offsets are handled when time of day matters.
For effective and end dates, make the boundary rule explicit. Receivers need to know whether the value is inclusive, exclusive, planned, actual, or merely informational.
OM7-14 is a timing field. Send the real source-system precision, do not pad unknown dates or times, and agree how timezone offsets are handled when time of day matters.
For effective and end dates, make the boundary rule explicit. Receivers need to know whether the value is inclusive, exclusive, planned, actual, or merely informational.
OM7-15 carries a measured, counted, priced, or dosed value. A number without the expected unit, currency, or companion qualifier is much easier to misread than an empty field.
OM7-16 supplies the units that make the companion numeric field meaningful. Units should be coded consistently, especially for medication, lab, specimen, and billing quantities.
The generated panel links this to HL7 table 0414; many real interfaces narrow that list further, so follow the receiver's implementation guide.
OM7-17 carries a measured, counted, priced, or dosed value. A number without the expected unit, currency, or companion qualifier is much easier to misread than an empty field.
OM7-18 supplies the units that make the companion numeric field meaningful. Units should be coded consistently, especially for medication, lab, specimen, and billing quantities.
The generated panel links this to HL7 table 0414; many real interfaces narrow that list further, so follow the receiver's implementation guide.
OM7-19 is a timing field. Send the real source-system precision, do not pad unknown dates or times, and agree how timezone offsets are handled when time of day matters.
For effective and end dates, make the boundary rule explicit. Receivers need to know whether the value is inclusive, exclusive, planned, actual, or merely informational.
OM7-20 identifies a person, provider, staff member, or contact involved in this master-file record. Use the structured name or provider datatype instead of flattening everything into display text.
OM7-21 places the master-file record in an organization, facility, department, room, bed, or location group. Keep physical location, owning department, and receiving facility separate when the datatype allows it.
This field can repeat. Use repetitions for separate real-world values, not as a workaround for putting several unrelated ideas in one field.
OM7-22 tells the receiver the state of this master-file record. Status fields often drive workflow branches, so use the agreed code and do not infer a status just because another field looks complete.
The coded value should follow HL7 table 0473 or the narrower table in the local profile.
OM7-23 tells the receiver the state of this master-file record. Status fields often drive workflow branches, so use the agreed code and do not infer a status just because another field looks complete.
The coded value should follow HL7 table 0136 or the narrower table in the local profile.
OM7-24 carries a measured, counted, priced, or dosed value. A number without the expected unit, currency, or companion qualifier is much easier to misread than an empty field.
The generated panel links this to HL7 table 0132; many real interfaces narrow that list further, so follow the receiver's implementation guide.