Data types by name

Each composite below has an interface, a parser (parseXxx(rep, enc)), an accessor on Field (field.asXxx()) and an encoder (encodeXxx(value), also reachable as encodeComposite("XXX", value)). Every interface is also a type in the HL7 namespace (HL7.EI). Read data types by name shows them in use.

Three rules hold for every type on this page:

• A component that is absent or empty is left out of the object, never set to undefined. An empty field reads as {}.
• A component past the named ones is kept, in order, on extraComponents, never dropped. An absent interior component there is "", so an index maps back to its HL7 component number.
• Values are the text the sender wrote, decoded once. Amounts, quantities and datetimes stay strings: a price is never rounded into a float, and a datetime keeps its precision until you read it with parseDtm.

A nested composite (an EI inside EIP, an MO inside CP, a coded element inside CQ) is read from the subcomponents of its component. When the nested value is empty, its key is left out rather than set to {}.

EI, EIP, CNE, DR, MO, CP, CQ, VID, MSG, PT and FC

The component names are the same from v2.5 to v2.9 for every type here. Where a component's own type changed between versions, the third column says how it is read.

EI: Entity Identifier

#	Property	Notes
1	entityIdentifier	the identifier itself
2	namespaceId	assigning authority, local name
3	universalId	assigning authority, an OID or a UUID
4	universalIdType	the kind of universalId (ISO, UUID, DNS)

Used by MSH-21, OBR-2, OBR-3, ORC-2 and ORC-3, among others. parseEi, asEi, encodeEi.

EIP: Entity Identifier Pair

#	Property	Notes
1	placerAssignedIdentifier	nested EI
2	fillerAssignedIdentifier	nested EI

Used by ORC-8, OBR-29 and SPM-2. parseEip, asEip, encodeEip.

CNE: Coded with No Exceptions

The 22 components of CWE under the same names (see CWE below). CNE differs in the standard's rule, not its shape: the code must come from the named table. The parser reads what was sent and does not enforce the rule. extraComponents starts at component 23. parseCne, asCne, encodeCne.

DR: Date/Time Range

#	Property	Notes
1	rangeStartDateTime	raw datetime text: a TS at v2.5, a DTM from v2.6
2	rangeEndDateTime	raw datetime text

At v2.5 each endpoint is a TS whose second part, the deprecated degree of precision, is a subcomponent; it is not read. parseDr, asDr, encodeDr.

MO: Money

#	Property	Notes
1	quantity	the amount as written, never a number
2	denomination	ISO 4217 currency code

parseMo, asMo, encodeMo.

CP: Composite Price

#	Property	Notes
1	price	nested MO
2	priceType	HL7 Table 0205
3	fromValue	as written
4	toValue	as written
5	rangeUnits	nested coded element: a CE at v2.5, a CWE from v2.6, read as a CWE
6	rangeType	HL7 Table 0298

Used by FT1-11, FT1-12 and PRC-5. parseCp, asCp, encodeCp.

CQ: Composite Quantity with Units

#	Property	Notes
1	quantity	as written
2	units	nested coded element: a CE at v2.5, a CWE from v2.6, read as a CWE

Used by TQ1-2. parseCq, asCq, encodeCq.

VID: Version Identifier

#	Property	Notes
1	versionId	HL7 Table 0104
2	internationalizationCode	nested coded element (CE at v2.5, then CWE)
3	internationalVersionId	nested coded element (CE at v2.5, then CWE)

Used by MSH-12. msg.meta.version still reads MSH-12.1 alone. parseVid, asVid, encodeVid.

MSG: Message Type

#	Property	Notes
1	messageCode	HL7 Table 0076
2	triggerEvent	HL7 Table 0003
3	messageStructure	HL7 Table 0354

Used by MSH-9. parseMsg, asMsg, encodeMsg.

PT: Processing Type

#	Property	Notes
1	processingId	HL7 Table 0103
2	processingMode	HL7 Table 0207

Used by MSH-11. msg.meta.processingId still reads MSH-11.1 alone. parsePt, asPt, encodePt.

FC: Financial Class

#	Property	Notes
1	financialClassCode	an IS up to v2.6, a CWE from v2.7; read as a nested coded element either way
2	effectiveDate	raw datetime text

A v2.5 code arrives as financialClassCode.identifier; a v2.7 one keeps its text and coding system too. Used by PV1-20. parseFc, asFc, encodeFc.

CWE components 10 to 22

v2.7 added thirteen components to CWE, and v2.8 and v2.9 keep them. They are now read by name:

#	Property
10	secondAlternateIdentifier
11	secondAlternateText
12	nameOfSecondAlternateCodingSystem
13	secondAlternateCodingSystemVersionId
14	codingSystemOid
15	valueSetOid
16	valueSetVersionId
17	alternateCodingSystemOid
18	alternateValueSetOid
19	alternateValueSetVersionId
20	secondAlternateCodingSystemOid
21	secondAlternateValueSetOid
22	secondAlternateValueSetVersionId

CWE.extraComponents still starts at component 10, as it did before these had names, so code that reads it by position keeps working. When you encode a CWE, a named field wins over the extraComponents entry at the same position.

The typed views that read EI

View	Field	Flat string beside it
msg.meta.messageProfileIdentifiers	MSH-21	none
order.placerOrderId	OBR-2	placerOrderNumber (EI.1 alone)
order.fillerOrderId	OBR-3	fillerOrderNumber (EI.1 alone)
order.orcPlacerOrderId	ORC-2	none
order.orcFillerOrderId	ORC-3	none

Two placers can issue the same order number, so match orders on the whole EI, not on the flat number alone.

ORC-2 and ORC-3 come from the ORC that precedes the order's OBR, as sent. They are never copied from OBR-2 or OBR-3.

The other named types

XPN, XAD, CX, CWE (components 1 to 9), CE, XTN, PL, TS, NM, SN, HD and XCN. Their component lists are in the API reference.