HL7 QSC Query Selection Criteria
HL7 datatype components QSC components from HL7 v2.5.1 Hide components
These are the generated components for the version selected at the top of the page. The article stays practical, and this panel follows the chosen HL7 version.
Components
QSC carries query selection criteria. It is an older query datatype, and it works only when both sides agree on the segment field name, relational operator, and value format.
In this guide, QSC appears in VTQ.5. That used-by list is a good reality check: the datatype is only half the story, and the field that uses it tells you the workflow.
The component panel above is expanded by default because most datatype pages are used as quick lookup pages. Start there for the exact HL7 v2.5.1 shape, then use the notes below for the practical gotchas.
QSC-1 to QSC-4: Component Quick Read
The generated component panel above is the formal quick lookup. The short version is below so you can scan the shape without counting carets by eye.
The table-backed components here are QSC-2, QSC-4. Keep those values to the table or value set your implementation guide names, especially when the field is crossing organization boundaries.
- QSC-1 Segment Field Name - Segment Field Name. Type ST.
- QSC-2 Relational Operator - Relational Operator. Type ID. Table 0209.
- QSC-3 Value - Value. Type ST.
- QSC-4 Relational Conjunction - Relational Conjunction. Type ID. Table 0210.
Practical Notes
Text still has to survive HL7 delimiters. If the source value can contain |, ^, ~, &, or a backslash, encode it before putting it into the message. Integration Soup and the HL7 parser helpers include HL7Encode and HL7Decode for that exact kind of cleanup.
In HL7 Soup Web, click a field that uses QSC and the interpretation view will show which component you are sitting in and where that value lives in the raw message. That is especially handy with compact datatypes because one missing caret can move every value after it.
Official and Reference Notes
For formal reference, compare the generated HL7 v2.5.1 panel above with the HL7 v2.5.1 datatype list and the HL7 Terminology data type code system. Local implementation guides can narrow allowed values, tables, and component usage.