LOINC®Documents

08.13.2009

Daniel J. Vreeman, PT, DPT, MScAssistant Research Professor | Indiana University School of Medicine

Research Scientist | Regenstrief Institute, Inc

Copyright © 2009

Clinical LOINC Tutorial

Overview

• Origins of a Document Ontology• HL7/LOINC Document Ontology Model• Evaluation, Evolution, Ongoing

Development– Empiric analyses

• Future directions

Origins of a Document Ontology

Rationale

• As with other domains, local systems have idiosyncratic names for clinical documents

• Need a common, controlled vocabulary• Needed for HL7 CDA standard

– HL7 v2 too

• Timeline– 06/2000 Document Ontology Task Force– 09/2003 First axis values and LOINC codes– ~2005 Expanded SMD domain– 10/2007 Revised axis value approval

Document Type Codes

• Created to provide consistent semantics for names of documents exchanged b/w independent systems

• Supported Uses– Retrieval– Organization– Preparation of templates– Display

Frazier P, Rossi-Mori A, Dolin RH, Alschuler L, Huff SM. The creation of an ontology of clinical document names. Stud Health Technol Inform. 2001;84(Pt 1):94-8.

What is a Document?

• Document = Collection of information– Sentences, sections– Distinguished from “panels”, which have

enumerated discreet contents

• Formal Document Ontology model/rules apply to “clinical notes”– Clinical document (per HL7 CDA), produced by

clinicians spontaneously or in response to a request for consultation

– Does not apply to “reports”, produced in response to an order for a procedure

Approach

• Started with empiric analysis of over 2000 document names– Mayo, 3M/Intermountain, VA in SLC, VA in

Nashville

• Find the level of granularity that best meets the exchange use case

Finding the Commonality

• Ultra-specific local names: – Dr. Evil’s Friday Afternoon Pain Clinic Note

• Generalizable elements: – Outpatient Pain Clinic Note

• Local codes may still be needed– Can send both local and universal codes in HL7– Mapping to the universal code enables

interoperability and aggregation

Document Ontology Model

Multi-axial / Poly-hierarchical

Names Based on Document Content

• Names based on the expected information content

• NOT based on the document format– Text, scanned images, structured entry

form, XML, etc would all have the same LOINC code if the information content was the same

Assume that these other important attributes would be sent in different fields of the message

What’s NOT in a Document Name

• Specific author• Specific location of service or dictation• Date of service• Status (e.g. signed, unsigned)• Security/privacy flags (protected)• Updates/amendments to a document

Assume that these other important attributes would be sent in different fields of the message

Model of Document Names• Subject Matter Domain

– E.g. Cardiology, Pediatric Cardiology, Physical Therapy

• Role– Author training/professional classification (not @ subspecialty)– E.g. Physician, Nursing, Case Manager, Therapist, Patient

• Setting– Modest extension of CMS’s definition (not equivalent to location)– E.g. Inpatient Hospital, Outpatient, Emergency Department

• Type of Service– Service or activity provided to/for the patient (or other subject)– E.g. Consultation, History and Physical, Discharge Summary

• Kind of Document– General structure of the document– E.g. Note, Letter, Consent

Rules for Constructing Names

• LOINC has enumerated value lists for axes• Names need a Kind of Document value and

at least one of the other four axes

• Combinations from within an axis– Allowed where they make sense (SMD, Service)– Represented with a plus (+)

• Makes use of the curly brace notation• LOINC Class = DOC.CLINRPT

Component Prop Time System Scale Method

<Type of Service> <Kind of Document> Find Pt <Setng> Doc <SMD>.<Role>

Example LOINC CodesComponent Prop Time System Scale Method

Group counseling note Find Pt Inpatent Hospital Doc {Provider}

Evaluaton and management note Find Pt Outpatent Doc {Provider}

Evaluaton and management note Find Pt {Setng} Doc {Provider}

History and physical note Find Pt {Setng} Doc {Provider}

Inital evaluaton note Find Pt {Setng} Doc Physician

Subsequent evaluaton note Find Pt {Setng} Doc Nurse Practtoner

{curly braces} notation: send that content as a separate item in the message (field or segment)

Hierarchy in LOINC• Constructed a first-pass Component hierarchy

based on the Type of Service axis– Ignored Kind of Document

• Multi-axial hierarchy is generated based on the component hierarchy – (available as separate download)

• Could imagine construction of other hierarchies, like context-specific use cases

Hierarchy in LOINC

Evaluation, Evolution, and Development

Ontology Evolution and Refinement

• Ongoing evaluation and evolution• Exceptional contributions from

Columbia University and the VA• In particular, expanded original SMD

value list with ABMS specialty names and iterative discussion

Shapiro JS, Bakken S, Hyun S, Melton GB, Schlegel C, Johnson SB. Document ontology: supporting narrative documents in electronic health records. AMIA Annu Symp Proc. 2005:684-8.

Iterative Evaluation Case Study: NYPH-CUMC

SMD Role Setng Type of Service Kind of Document Overall Distnct

Original CDO 26.7% 99.9% 99.9% 43.5% 100% 23.4%

(n=894)

7.9%

Expanded CDO 98.6% 100% 100% 99.9% 99.9% 98.5%

(n=935)

39.1%

• Hyun S, Shapiro JS, Melton G, Schlegel C, Stetson PD, Johnson SB, Bakken S. Iterative evaluation of the Health Level 7--Logical Observation Identifiers Names and Codes Clinical Document Ontology for representing clinical document names: a case report. J Am Med Inform Assoc. 2009 May-Jun;16(3):395-9.

• Summary• More documents could be fully specified in with the expanded CDO• Many documents map to one LOINC code – factor of local names

and suitable LOINC values• Inter-rater reliability was very good

Nursing

• In a separate analysis, 38% of the section headings (n=308) from nursing documents could be mapped to existing LOINC codes

• Hyun S, Bakken S. Toward the creation of an ontology for nursing document sections: mapping section names to the LOINC semantic model. AMIA Annu Symp Proc. 2006:364-8.

SMD Role Setng Type of Service Kind of Document Overall Distnct

SMD-enhanced CDO (2005)

74% 100% 100% 100% 100% 74.5%

(n=94)

33%

Hyun S, Shapiro JS, Melton G, Schlegel C, Stetson PD, Johnson SB, Bakken S. Iterative evaluation of the Health Level 7--Logical Observation Identifiers Names and Codes Clinical Document Ontology for representing clinical document names: a case report. J Am Med Inform Assoc. 2009 May-Jun;16(3):395-9.

German University Hospital

• Used LOINC v2.24 (original DocOnt terms)• Of 86 the document types for 1.2 million

documents:– 44% mapped to LOINC– 44% had available mapping deemed not specific

enough– 12% had no LOINC match

• A LOINC code existed for 93.1% of documents in their set (by volume)

Dugas M, Thun S, Frankewitsch T, Heitmann KU. LOINC codes for hospital information systems documents: a case study. J Am Med Inform Assoc. 2009 May-Jun;16(3):400-3.

Ongoing Development

Ongoing Development

• A work-in-progress• LOINC Users’ Guide is the definitive

source for current policy– Always available at http://loinc.org

• Collaboration/discussion– Clinical LOINC meetings, HL7 SDTC– LOINC website– LOINC Users’ Forum: http:/forum.loinc.org

Future Directions

Future Directions

• Continued harmonization of v1 and v2 axis values

• Axis definitions• Extension/refinement to other Kind of

Documents• Empiric analysis of document contents