HL7 NST Application control level statistics
HL7 field reference NST 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 |
|---|---|---|---|---|---|
| NST.1 | Statistics Available | Yes | No | ID | 0136 |
| NST.2 | Source Identifier | No | No | ST | |
| NST.3 | Source Type | No | No | ID | 0332 |
| NST.4 | Statistics Start | No | No | TS | |
| NST.5 | Statistics End | No | No | TS | |
| NST.6 | Receive Character Count | No | No | NM | |
| NST.7 | Send Character Count | No | No | NM | |
| NST.8 | Messages Received | No | No | NM | |
| NST.9 | Messages Sent | No | No | NM | |
| NST.10 | Checksum Errors Received | No | No | NM | |
| NST.11 | Length Errors Received | No | No | NM | |
| NST.12 | Other Errors Received | No | No | NM | |
| NST.13 | Connect Timeouts | No | No | NM | |
| NST.14 | Receive Timeouts | No | No | NM | |
| NST.15 | Application control-level Errors | No | No | NM |
NST carries application control-level statistics for monitoring interface or application health.
The standard describes NST this way: The NST segment allows application control-level statistical information to be passed between the various systems on the network. Some fields in this segment refer to portions of lower level protocols; they contain information that can be used by application management applications monitoring the state of various network links.
Equipment and specimen-control segments are used around instruments, analyzers, containers, device commands, device status, and test configuration. They are practical plumbing for lab and automation workflows.
The main trap is treating an equipment status as if it were a clinical result, or treating a specimen/container identifier as if it were interchangeable with a patient or order identifier. Keep the layers separate.
The v2.5.1 structures show NST in NMD_N02 - Application management data message (unsolicited), NMQ_N01 - Application management query message, and NMR_N01 - Application management query 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.
NST-1 carries Statistics Available for this equipment or specimen workflow. 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 0136; many real interfaces narrow that list further, so follow the receiver's implementation guide.
NST-2 identifies the Source Identifier for this equipment or specimen workflow. Send the identifier that the receiving system actually keys on, and keep the assigning authority or coding system visible when the datatype supports it.
NST-3 qualifies the equipment or specimen workflow rather than identifying it. This is the sort of field receivers often use for branching, filtering, or display grouping.
Use the agreed value set, starting from HL7 table 0332. A local code without an agreed coding system is a small ambiguity that becomes a mapping problem later.
NST-4 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.
NST-5 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.
NST-6 is used for reconciliation. The receiver may compare it with the segments, batches, messages, rows, or items actually received, so do not populate it from a stale estimate.
NST-7 is used for reconciliation. The receiver may compare it with the segments, batches, messages, rows, or items actually received, so do not populate it from a stale estimate.
NST-8 carries Messages Received for this equipment or specimen workflow. 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.
NST-9 carries Messages Sent for this equipment or specimen workflow. 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.
NST-10 carries Checksum Errors Received for this equipment or specimen workflow. 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.
NST-11 carries Length Errors Received for this equipment or specimen workflow. 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.
NST-12 carries Other Errors Received for this equipment or specimen workflow. 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.
NST-13 carries Connect Timeouts for this equipment or specimen workflow. 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.
NST-14 carries Receive Timeouts for this equipment or specimen workflow. 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.
NST-15 qualifies the equipment or specimen workflow rather than identifying it. This is the sort of field receivers often use for branching, filtering, or display grouping.