1.Mapping from SNOMED CT to ICD-10 and ICD-10-CM
Dr. Kin Wah Fung
U.S. National Library of Medicine,
Bethesda, MD, USA
2.Background
SNOMED CT is inherently more suitable for clinical documentation in an Electronic Health Record (EHR)
Content coverage
Clinical orientation
Flexible data entry and retrieval
Extensibility
Requirements for ICD-10 (mortality report to WHO) and ICD-10-CM (reimbursement starting Oct 2013) codes have a strong influence on EHR development
A map from SNOMED CT to ICD will promote the use of SNOMED CT for clinical documentation while allowing the generation of administrative codes
Other potential benefits: improve speed and quality of ICD coding
3.Two mapping projects
Mapping SNOMED CT to ICD-10
Joint effort between IHTSDO and WHO
International participation (including USA, UK, Canada, Sweden, Australia, and New Zealand)
Funded by IHTSDO with a lot of volunteer contribution
Mapping SNOMED CT to ICD-10-CM
Led by NLM with direct involvement from National Center for Health Statistics (NCHS)
Methodology and tools – based on ICD-10 Map project
A lot of overlap between the 2 projects – people, methodology, tooling, mapping data
5.Multiple ICD codes – dagger and asterisk
Source concepts which map to ICD chapters with asterisk conventions will be mapped to two target codes.
The asterisk classification will always be the second map group
Source concept: 111900000 Pneumonia in aspergillosis (disorder)
Map group 1
Rule 1 → B44.1 Other pulmonary aspergillosis
Map group 2
Rule 1 → J17.2 Pneumonia in mycoses
6.Multiple ICD codes – External causes
The source concepts denoting a condition with an identifiable cause within scope of ICD‑10 chapter XX(20) will be mapped to two target codes.
The external cause code will be assigned to the second target record.
Source concept: 242012005 Thermal burns from lightning (disorder) :
Map group 1
Rule 1 → T30.0 Burn of unspecified region
Map group 2
Rule 1 → X33 Victim of lightning
7.Map rule – gender
Source concept: 8619003 Infertile (finding)
Map group 1
Rule 1 IFA 1086007| FEMALE (FINDING) | → N97.9 Female infertility, unspecified
Rule 2 IFA 248153007 | MALE (FINDING) | → N46 Male infertility
Rule 3 OTHERWISE TRUE -> NULL
www.ihtsdo.org
8.Map rule – age of onset
Source concept: 32398004 Bronchitis (disorder)
Map group 1
Rule 1 IF 44518008 | AGE AT ONSET OF CLINICAL FINDING (OBSERVABLE)| < 15 YEARS → J20.9 Acute bronchitis, unspecified
Rule 2 OTHERWISE TRUE → J40 Bronchitis not specified as acute or chronic
www.ihtsdo.org
10.Map advice
Explicit guidance on the map’s usage
DESCENDANTS NOT EXHAUSTIVELY MAPPED
EPISODE OF CARE INFORMATION NEEDED
CONSIDER ADDITIONAL CODE TO IDENTIFY SPECIFIC CONDITION OR DISEASE
CONSIDER LATERALITY SPECIFICATION
CONSIDER TRIMESTER SPECIFICATION
CONSIDER WHICH FETUS IS AFFECTED BY THE MATERNAL CONDITION
POSSIBLE REQUIREMENT FOR AN EXTERNAL CAUSE CODE
THIS IS A MANIFESTATION CODE FOR USE IN A SECONDARY POSITION
THIS IS AN EXTERNAL CAUSE CODE FOR USE IN A SECONDARY POSITION
www.ihtsdo.org
11.Dual independent mapping
Built-in quality assurance process – each map has to be agreed by 2 independent sources
Concepts with no legacy maps – mapped independently by 2 map specialists
Concepts with legacy maps – mapped by 1 map specialist first, and by another if there is discordance between legacy map and 1st map specialist
Sources of legacy maps
Existing UK maps (to ICD-10)
CMT maps (to ICD-10-CM)
UMLS synonymy
ICD-10-CM maps derived from finalized ICD-10 maps
Minor conflicts resolved by map leads
Otherwise referred for broader discussion or consensus management panel
12.Intended uses of the map
Embedded in the EHR for real-time, interactive ICD codes generation (I-MAGIC=Interactive Map-Assisted Generation of ICD Codes)
To assist coding professionals by suggesting ICD codes based on SNOMED CT-encoded problem list entries
13.Interactive Map-Assisted Generation of ICD Codes (I-MAGIC) Algorithm
14.SNOMED CT concepts that are in scope for mapping
Any concept in the following three SNOMED CT hierarchies
Clinical finding
Event
Situation with explicit context
Total about 110,000 concepts in scope
www.ihtsdo.org
15.Priorities for phase 1 work
ICD-10 map
NLM’s CORE Problem List Subset
SNOMED CT concepts that correspond to top ranking ICD-10 codes in 5 countries
ICD-10-CM map
NLM’s CORE Problem List Subset
Donated content from Kaiser Permanente’s Convergent Medical Terminology (CMT) – top 2,500, sub-specialty subsets (cardiology, neurology, mental health, musculo-skeletal)
16.Work progress
ICD-10 map
Preview publication of maps for 5,000 concepts in September 2011
Final publication of phase 1 maps (about 20,000 concepts) planned for April 2012
ICD-10-CM map
Planned release dates
Feb 2012 – preview release (6,000 concepts)
June 2012 – full phase 1 maps (15,000 concepts)