The `LOINC.tab' and `LOINC+.tab' Databases

Description

The Regenstrief Institute of Indianapolis compiled the "Laboratory Observations Names and Codes" (LOINC) code in order to have a unique set of identifiers for observations for use with HL7. The advantage of this code is that (1) it is freely available, (2) it is planned to extend the code beyond laboratory observations in order to map also clinical terms, and (3) it tries to refer to other coding systems (ASTM and IUPAC) where applicable. Even though the LOINC code is not perfect, neither in its concepts, nor in it's degree of reaching it's own aims, it seems feasible to use it as an integral part of ProtoGen/HL7 applications for observation identifiers.

The LOINC code is sizeable (over 6000 entries) so that it deserves to be used only as a compiled, hashed and indexed database for quickly referencing its entries. A textual version is used for editing and extending the database. The "manager" program, loincmgr, is used to convert between the two representations of the LOINC database.

The following attributes are defined, of which only the most important are explained here. Please refer to the LOINC manual for more.

loinc_num @rm{(key)}

LOINC number with check digit separated by a `-', e.g. `5914-7'

measure @rm{(indexed)}

a string, e.g. `GLUCOSE'

property

the dimension, e.g. `SCNC' for substance concentration.

timing

specimen

the specimen, e.g. `BLD' for blood

precision

method

relat_nms @rm{(indexed for each entry)}

a semicolon separated list of (probably non-unique) alias names

mclass @rm{(indexed)}

source @rm{(indexed)}

euclide_cd @rm{(indexed)}

astm_cd @rm{(indexed)}

iupac_cd @rm{(indexed)}

references to other code systems (most of which are still void)

dt_last_ch

comments

answerlist

status

scope

snomed_cd

va_cd

metpath_code @rm{(indexed)}

hcfa_code

references to other code systems (most of which are still void)

norm_range

normal range, about all are still void

units

functional dependent to property, still left void

map_to

Since the LOINC coding scheme tries to map measure x dimension x specimen x other specifiers to one loinc number, the list is likely to be incomplete regarding other specimen or dimensions for the same measure. Moreover the list is incomplete even regarding measures, e.g. those needed for acid base analysis. The LOINC thus requires extension if it is to be usefully applied. Modifications to the original LOINC database are not allowed, but additions are still possible if assigned loinc numbers that do not interfere with existing ones. This can be achieved by numbering the additions from 9999 backwards. The additions that are defined for this Interfacing project are bundled in the file LOINC+.tab while the original LOINC code is found in LOINC.tab.

The `.tab' file format for the LOINC code is optionally quoted (`"') strings separated by tabs one line per row. Comments are not allowed. Care should be taken that the table contains only valid lines and no empty ones.

Examples

"9984"	"BODY TEMPERATURE"	"TEMP"	"PT"	"PAT"	"QN"	"MEASURED"	""	"CLIN"	"GUSW"	""	""	""	""	""	""	""	""	""	""	""	""	""	""	""
"9999"	"OXYGEN^^SATURATION ADJUSTED TO 0.5"	"PRES"	"PT"	"BLDA" "QN"	""	
     "PO2(50);P50"	"CHEM"	"GUSW"	""	""	""	""	""	""	""	""	""	""	""	""	""	""	""
"9998"	"OXYGEN^^SATURATION ADJUSTED TO 0.5"	"PRES"	"PT"	"BLDC" "QN"	""	
     "PO2(50);P50"	"CHEM"	"GUSW"	""	""	""	""	""	""	""	""	""	""	""	""	""	""	""
"9997"	"OXYGEN^^SATURATION ADJUSTED TO 0.5"	"PRES"	"PT"	"BLDV" "QN"	""	
     "PO2(50);P50"	"CHEM"	"GUSW"	""	""	""	""	""	""	""	""	""	""	""	""	""	""	""

Files

`/usr/hl7/etc/LOINC.tab'

the original LOINC code table

`/usr/hl7/etc/LOINC+.tab'

the table of extensions

`/usr/hl7/lib/codes/LOINC.db'

the compiled, hashed and indexed database

See Also

section Managing the LOINC Code Database section Configuring Results Mapping