This document provides an overview of how LOINC (Logical Observation Identifiers Names and Codes) codes can be used with FHIR (Fast Healthcare Interoperability Resources). It discusses how LOINC codes are represented and used in various FHIR resources like Observation, Questionnaire, DiagnosticReport, etc. It also describes how FHIR terminology services can be used to retrieve information about LOINC codes and structures like parts, answer lists, and properties to build value sets. The document demonstrates how LOINC enhances interoperability when clinical data is coded with LOINC and accessible via FHIR.

1. Daniel J. Vreeman, PT, DPT, MS, FACMI
Regenstrief-McDonald Scholar in Data Standards
Indiana University School of Medicine
Director, LOINC and Health Data Standards
Regenstrief Center for Biomedical Informatics
FHIR DevDays 2017 | Amsterdam, Netherlands
© 2017
@djvreeman
FHIR and LOINC

2. FHIR and LOINC go together
like chips and salsa
photo via Marco Verch

3. Overview
1. Introduction to LOINC
2. LOINC in the FHIR jungle
3. LOINC specific features in the
FHIR terminology services
photo via Vernio77

4. Disclosure
I’m the author of the book LOINC Essentials published
by Blue Sky Premise, LLC where I serve as President.
Not a NYT Best Seller. Net profit going to a special
charitable project: danielvreeman.com/build-a-school
PI on a contract from bioMérieux for LOINC content

5. First, let’s get a
sense of who’s here
photo via Arran Moffat

6. Not much, I’m new
I’m relatively new
I’m an advanced LONICer
What is your familiarity with LOINC?

7. LOINC’s superhero
origin story
McDonald et al. Canopy Computing: using the Web in Clinical Practice. JAMA. 1998;280(15):1325-1329.

8. Life without LOINC
CODE NAME
34626D Arterial BP Diastolic
39312D ABP Diastolic
ARTDIASBP Arterial Diastolic BP
nvArtBPS Arterial Blood Pressure Diastolic
DBP DBP
25284D BP (NIBP)
2737317 Diastolic Blood Pressure #1
6881D BP Diastolic
3800DBP BP
77934D BP Manual Diastolic
919109 Diastolic Blood Pressure
DiastBP DiastolicBP
PBPD PRE BLOOD PRESSURE DIASTOLIC
POBPD POST BLOOD PRESSURE DIASTOLIC

9. MO MONEY MO PROBLEMS

10. MO DATA MO PROBLEMS

11. MO DATA MO PROBLEMS
It's like, the more money
we come across
The more problems we see
data

12. Problems
Health IT systems often lack
common mechanisms for
exchanging data.
Even when they do, they use
different ways of identifying the
same concept.
MO DATA MO PROBLEMS
Only way to overcome these problems is
with data standards

13. Est. 1994
The universal standard for
identifying health measurements,
observations, and documents.

14. LOINC is a rich trove of 84,000+ standardized variables
Lifestyle
Lab and clinical Environmental
21654-9 CFTR gene targeted mutation analysis
24475-6 F2 gene c.20210G>A [Presence]
75547-0 Noninvasive prenatal fetal aneuploidy
and microdeletion panel based on Plasma cell-
free+WBC DNA by Dosage of chromosome-specific
circulating cell free (ccf) DNA
82245-2 Chromosome region 22q11.2 deletion in
Amniotic fluid or CVS by FISH
4548-4 Hgb A1c MFr Bld
8462-4 Diastolic blood pressure
24725-4 Head CT
57021-8 CBC W Auto Differential panel - Blood
8633-0 QRS duration
41950-7 Number of steps in 24 hour Measured
75296-4 Carbohydrate intake 24 hour Estimated
82289-0 Rating of perceived exertion [Score]
72166-2 Tobacco smoking status NHIS
64098-7 Distance walked in 6 minutes
82464-9 Mosquito count [#] in Environmental specimen
67784-9 Individuals below poverty line Neighborhood
63736-3 Materials to which you were exposed in your
work or daily life
63805-6 How long did you handle paints or solvents
yourself?
67640-3 My teachers believe that I can do well in my
school work
Genetics

15. No single vocabulary
standard covers it all
Observables (and collections of them): LOINC
Diagnosis, Problems, Organisms, etc: SNOMED CT
Medications: RxNorm, ACT
Reimbursement: National codesets (e.g. CPT)

16. We do measurements
LOINC is focused on one piece of
the interoperability puzzle
photo via puuikibeach| cc-by

17. Laboratory LOINC

18. Clinical LOINC

19. Designed For Observations
Using Hl7 FHIR + LOINC

20. Anatomy of a LOINC Term
LOINC Code 18262-6
Component Cholesterol.in LDL
Property MCnc
Timing Pt
System Ser/Plas
Scale Qn
Method Direct assay
18262-6:Cholesterol.in LDL:MCnc:Pt:Ser/Plas:Qn:Direct assay
There are six major LOINC axes

21. Anatomy of a LOINC Term
LOINC Code 8302-2
Component Body height
Property Len
Timing Pt
System ^Patient
Scale Qn
Method
8302-2:Body height:Len:Pt:^Patient:Qn:
Method is the only optional axis

22. Codes for individual observations
Codes for collections(panels and documents)
6690-2 Leukocytes [#/volume] in Blood by Automated count
2339-0 Glucose [Mass/volume] in Blood
29463-7 Body weight
55423-8 Number of steps in unspecified time Pedometer
57021-8 CBC W Auto Differential panel - Blood
34565-2 Vital signs, weight and height panel
44249-1 PHQ-9 quick depression assessment panel
36813-4 CT Abdomen and Pelvis W contrast IV
18842-5 Discharge summary

23. Structured Answer Lists
Answer List Attributes
ID (contains “LL” prefix)
OID
External Link
Answer Item Attributes
ID (contains “LA” prefix)
String
Sequence
Local code
Universal code (SNOMED CT)
Score

24. Normative => This is it. Don’t
mess with it!

25. The LOINC Distribution
LOINC Table
LOINC Table Core
LOINC Part File
LOINC Answer File
LOINC Panels and Forms File
LOINC Document Ontology File
LOINC Multiaxial Hierarchy File
LOINC/IEEE Medical Device Code Mapping File
LOINC/RSNA Radiology Playbook File
LOINC/SNOMED CT Expression Association and Map Sets
Each has a detailed ReadMe and Release Notes

26. Major releases
twice per year
(June and December)
photo via striatic | cc-by

27. LOINC grows
because USERS ask

28. LOINC License
No cost use
Worldwide
In perpetuity
Commercial or noncommercial
purposes
Encourages translation
One major prohibition…

29. CANNOT use any
Licensed Material to
develop or promulgate
a different standard for
orders or observations.

30. One more thing…
what’s with the pig?

31. LOINC adoption around the
world
Global Growth

32. 55,000+ registered users from 170 countries
6,000 new users per year

33. Many kinds of LOINC Users
Referral / reference labs and radiology centers
Health-related federal agencies
Care organizations
Professional societies
Health information exchange networks
Insurance companies
Health IT vendors
Instrument manufacturers
Health app developers

34. Official national standard in 30+ countries

35. LOINC in the
FHIR Jungle

36. Diagnostic Medicine Module

37. Observation
LOINC is the most widely
used code system for
observations
Here’s“classic” numeric result
reporting example with
UCUM units

38. Return hemoglobin
Obs for my patient
http://spark.furore.com/fhir/Observation?
patient=http://spark.furore.com/fhir/Patient/
f001&code=718-7&_format=json

39. Return patients with
a hemoglobin Obs
http://spark.furore.com/fhir/Patient?
_has:Observation:patient:code=718-7&_format=json
Reverse chaining

40. Observation
Works just as well for coded
answers like this one where
you may also use LOINC
Answer codes

41. Specific LOINC codes for
each of these more
precisely specified
Observations
Profile [Observation]: Genetics

42. Profile [Observation]: Genetics

43. Profile [Observation]: Vital Signs

44. Goal
Use LOINC inside the
Goal resource as the
code for target measure

45. Diagnostic Report
The findings and interpretation of
diagnostic tests.
Some mix of atomic results, images,
textual and coded interpretations,
and formatted representation of
diagnostic reports.
For lab, pathology, radiology, and
other diagnostic services
(cardiology, etc)
LOINC is preferred code set

46. Imaging Study
Diagnostic Report can point to
Imaging Study
Diagnostic Report would typically
be a document in a presented
form and the narrative, with an
imaging study reference and
possibly some key images.
Imaging Study provides
information on a DICOM imaging
study, and the series and imaging
objects in that study.
loinc.org/collaboration/rsna
vs. Diagnostic Report

47. Foundation Module

48. Questionnaire
(and Response)
LOINC has a rich data model
for representing collections,
data elements (questions), and
their answers.
10,000+ LOINC terms for
patient reported outcomes
measures

49. A quick sample of
the LOINC
questionnaire/
assessment
content

50. Social, psychological and behavioral
observations - 2015 Edition Health IT
Certification Criteria set
Adverse Childhood Events
Borderline Symptom List - 23 Item
Brief Interview for Mental Status (BIMS)
Confusion Assessment Method (CAM)
Core behavioral health terms (SAMHSA)
Edinburgh Postnatal Depression Scale
FACIT
Geriatric Depression Scale (GDS)
Humiliation, Afraid, Rape, and Kick
questionnaire
HIV Signs and Symptoms Checklist
howRU
Living with HIV (LIV-HIV)
Morse Fall Scale
My Mood Monitor
Neuro-QOL
PROMIS
PhenX
PHQ
VR 12 and 36
10,000+ patient assessment terms
Adding more all the time
Vreeman DJ, McDonald CJ, Huff SM. Representing patient assessments in LOINC®. AMIA Annu Symp Proc. 2010;832-836. PMID: 21347095 .
Vreeman DJ, McDonald CJ, Huff SM. LOINC® - A Universal Catalog of Individual Clinical Observations and Uniform Representation of Enumerated Collections. Int J Funct Inform
Personal Med. 2010;3(4):273-291.

51. Composition
Basic structure that
builds FHIR Documents
(immutable bundles with
attested narrative)
LOINC has a rich set of
clinical document type
and section codes (used
extensively in CDA).
loinc.org/document-ontology

52. DataElement
Individual pieces of data that might
be collected or stored, including
observations requested or
performed and questions on forms
A fair bit of overlap b/w LOINC
attributes and DE definition
(question text, answer list, etc)
LOINC could serve as primary
identifier for many

53. Security/Privacy Module

54. Consent
A record of a healthcare
consumer’s policy choices, which
permits or denies identified
recipient(s) or recipient role(s) to
perform one or more actions within
a given policy context, for specific
purposes and periods of time.
In its Document Ontology, LOINC
provides a set of codes for consent
documents that can be used as the
category codes.

55. LOINC-specific
features in FHIR TS
Cool tricks with LOINC via FHIR’s Terminology Services

56. https://www.hl7.org/fhir/loinc.html

57. URI
http://loinc.org
Codes
LOINC Codes (21176-3)
LOINC Parts (LP31755-9)
LOINC Answer Lists (LL715-4)
LOINC Answer Codes (LA11165-0)
Display Names for LOINC terms
Long Common Name
Short Name (less than 40 characters)

58. Inactive
ACTIVE=DEPRECATED
Subsumption
Defined by LOINC MultiAxial
Hierarchy

59. Get info about your
favorite LOINC term
http://test.fhir.org/r3/CodeSystem/$lookup?
system=http://loinc.org&code=39046-8&_format=json

60. Quick note about
legal stuff
http://loinc.org/license

61. If you are building value sets (or
other web-accessible artifacts/
documents) that contain LOINC
codes, you must include a
copyright notice (per the license)
<copyright value="This content LOINC® is copyright © 1995 Regenstrief
Institute, Inc. and the LOINC Committee, and available at no cost
under the license at http://loinc.org/terms-of-use"/>

62. LOINC Parts
Coded representation of LOINC Fully
Specified Name attributes
Codes have the “LP” prefix
Represent them in UPPERCASE:
LP15491-1
Some Parts makeup MultiAxial Hierarchy
Other Part uses:
LOINC-specific filter properties
StructureDefinitions
ConceptMap (e.g. Part maps to SNOMED, RadLex, RxNorm)

63. Get child LOINCs under a Part
from the Multiaxial Hierarchy
A value set with an identifier of "http://loinc.org/vs/[partcode]"
http://test.fhir.org/r3/ValueSet/$expand?
url=http://loinc.org/vs/LP15491-1

65. LOINC Answer Lists
Value sets of answers for observation
value of ordinal/nominal LOINC terms
Lists are given a code (LL prefix)
LOINC Answer File specifies the binding
strength (Example, Preferred, Normative)
Some lists are intensional, many are
enumerated in LOINC
LOINC Answer strings are given codes
(LA prefix)

66. Get a LOINC Answer
List value set
http://test.fhir.org/r3/ValueSet/$expand?
url=http://loinc.org/vs/LL378-1&_format=json

68. LOINC Properties
STATUS
COMPONENT
PROPERTY
TIME_ASPCT
SYSTEM
SCALE_TYP
METHOD_TYP
CLASS
CLASSTYPE
ORDER_OBS
1=Lab, 2=Clinical, 3=Claims Attachments, 4=Surveys
Order, Observation, Both

69. Building Value Sets
Based on LOINC
Properties

70. Include:
Component of Body height
Property of Len
System of ^Patient
Exclude:
None
Include special circumstances like post-partum, standing, etc

71. http://localhost:10000/vocab/ValueSet/test-
vs6/$expand?_format=json

72. Include:
Component of Glucose
Property of MCnc
System of Bld*
Exclude:
System of Bld.dot or BldC

73. http://localhost:10000/vocab/ValueSet/test-
vs5/$expand?_format=json

74. Include:
Method of Sports Medicine
Scale of Doc
Exclude:
None

75. http://localhost:10000/vocab/ValueSet/test-
vs7/$expand?_format=json

76. Work in Progress:
Canonical representation of LOINC as a
FHIR Code System
photo via Arul Irudayam | by-nd

77. https://loinc.org/fhir/loinc.xml

78. Take home lesson:
When clinical data is coded with LOINC
codes and made accessible by FHIR,
diverse IT applications can understand
and interact with it for the benefit of
many in the health ecosystem.
photo via IMLS DCC | cc-by