HL7 CD Channel Definition
HL7 datatype components CD 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
| Pos | Component | Name | Type | Table | Description |
|---|---|---|---|---|---|
| 1 | CD.1 | Channel Identifier | WVI | Channel Identifier; Type WVI. | |
| 2 | CD.2 | Waveform Source | WVS | Waveform Source; Type WVS. | |
| 3 | CD.3 | Channel Sensitivity/Units | CSU | Channel Sensitivity/Units; Type CSU. | |
| 4 | CD.4 | Channel Calibration Parameters | CCP | Channel Calibration Parameters; Type CCP. | |
| 5 | CD.5 | Channel Sampling Frequency | NM | Channel Sampling Frequency; Type NM. | |
| 6 | CD.6 | Minimum/Maximum Data Values | NR | Minimum/Maximum Data Values; Type NR. |
CD describes a waveform channel. It is a specialist datatype for waveform observations rather than the day-to-day coded element most HL7 interfaces use. If you are not moving waveform data, this page is mainly a reference lookup.
You will mostly meet CD in waveform-related profiles. If your interface is not moving waveform observations, it is enough to recognize the datatype and leave the detailed handling to the profile that introduces it.
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.
CD-1 to CD-6: 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.
- CD-1 Channel Identifier - Channel Identifier. Type WVI.
- CD-2 Waveform Source - Waveform Source. Type WVS.
- CD-3 Channel Sensitivity/Units - Channel Sensitivity/Units. Type CSU.
- CD-4 Channel Calibration Parameters - Channel Calibration Parameters. Type CCP.
- CD-5 Channel Sampling Frequency - Channel Sampling Frequency. Type NM.
- CD-6 Minimum/Maximum Data Values - Minimum/Maximum Data Values. Type NR.
Practical Notes
Keep numeric values numeric. Do not mix display formatting, unit text, or currency labels into the number component when the datatype has a separate place for that meaning. A format validator for whole numbers or decimals is a simple way to catch this before the receiving system has to complain.
In HL7 Soup Web, click a field that uses CD 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.