HL7 data types define the kind of data that can be included in a field, and are used throughout the HL7 message structure. Examples would be a string, formatted text, timestamp, address, or coded element. Each data type may contain additional data types that are referenced as components or subcomponents. Complex data types use other data types to define the kind of data they can contain.
Certain data types cannot reference each other due to the nature of the components. For instance, a data type cannot reference data types that already reference multiple components, because there is no way to code the information at that level.
Below is a list of the HL7 data types:
DATA TYPE CATEGORY/ DATA TYPE
DATA TYPE NAME
Alphanumeric
ST
String
TX
Text data
FT
Formatted text
Numerical
CQ
Composite quantity with units
MO
Money
NM
Numeric
SI
Sequence ID
SN
Structured numeric
Identifier
ID
Coded values for HL7 tables
IS
Coded values for user-defined tables
HD
Hierarchic designator
EI
Entity identifier
RP
Reference pointer
PL
Person location
PT
Processing type
Date/Time
DT
Date
TM
Time
TS
Time stamp
Code Values
CE
Coded element
CF
Coded element with formatted values
CK
Composite ID with check digit
CN
Composite ID number and name
CX
Extended composite ID with check digit
XCN
Extended composite ID number and name
Generic
CM
Composite
Demographics
AD
Address
PN
Person name
TN
Telephone number
XAD
Extended address
XPN
Extended person name
XON
Extended composite name and ID number for organizations
XTN
Extended telecommunications number
Specialty/Chapter specific
CD
Channel definition
MA
Multiplexed array
NA
Numeric array
ED
Encapsulated data
CP
Composite price
FC
Financial class
Extended Queries
QSC
Query selection criteria
QIP
Query input parameter list
RCD
Row column definition
Master Files
DLN
Driver’s license number
JCC
Job code/class
VH
Visiting hours
Medical Records/Info Mgmt
PPN
Performing person time stamp
Time Series
DR
Date/time range
RI
Repeat interval
SCV
Scheduling class value pair
TQ
Timing/quantity
Understanding components and subcomponents
A data type may reference one or more additional data types as components or subcomponents. For example, the CK (composite ID with check digit) data type can be broken down into four components, each referencing a specific data type. One of these components (HD) also references three other data types as subcomponents.
