HPO to SNOMED mapping - the objectives
The objectives was to produce a mapping to a fully logically defined target, so that if a direct map to a SNOMED concept was not available, an expression was constructed
using Compositional Grammar and post-coordination. The map produced would then be used usually during configuration of healthcare systems or in an expression repository.
Above is an illustration of the structure and components of an expression, including the focus concept, attributes and attribute value.
Expressions, Post-coordination resources
These expressions have been authored using the following resources and validated against the April 2024 Release of SNOMED International;
- Machine Readable Concept Model-https://browser.ihtsdotools.org/mrcm/?branch=MAIN%2F2020-07-31
- Postco-ordination demonstrator - expression validation (classification) -Postcoordination Implementation Demo (ihtsdo.github.io)
- Practical Guide to Post-coordination -https://snomed.org/postcoordination
- SNOMED International browser
HPO to SNOMED Cross Mapping - the results
Based on the HPO release of August 2024, and the SNOMED International release of April 2024, the mapping results are given below.
Note that 86% of the HPO terms are mappable either directly or involving an expression, so that the missing 13% could potentially be reduced with new SNOMED content.
The expressions have been validated using the Post-coordination Demonstrator resource. (Postcoordination Implementation Demo (ihtsdo.github.io))
| Group | Number (%) |
|---|---|
| One to one map | 7184 (41%) |
| One to many | 81 (0.5%) |
| Map with expression | 7833 (45%) |
| Map to parent | 2338 (13.4%) |
| Clarification | 22 (0.1%) |
| Out of scope | 685 (3.9) |
| Total | 18,370 |
Examples of post-coordination
Below are examples of the common types of expressions generated. Whilst the process is essentially manual, by using a structured and repeatable approach, expressions can be produced which
pass validation and are consistent and clinically valid. The supporting resources indicates above should be used but combined with a wide knowledge of the topic.
HPO concept | SNOMED post-coordinated expression | ||
|---|---|---|---|
1 | HP:0001525 Severe failure to thrive | 54840006 |Failure to thrive (disorder)|: {246112005 |Severity (attribute)|=24484000 |Severe (severity modifier) (qualifier value)|} | approx (45%) |
2 | HP:0004363 Abnormal circulating calcium concentration. | 1217344005 |Finding of blood substance level (finding)|: {363713009 |Has interpretation (attribute)| =394844007 |Outside reference range (qualifier value)|, 363714003 |Interprets (attribute)| =312472004 |Blood calcium measurement (procedure)|} | approx 30% |
3 | HP:6000554 Positive bloodstream plasmodium falciparum nucleic acid pathogen test. | 434156008 |Infectious agent in bloodstream (finding)|: {363713009 |Has interpretation (attribute)| = 10828004 |Positive (qualifier value)|, 363714003 |Interprets (attribute)| = (398545005 |Nucleic acid assay (procedure)|: 246093002 |Component (attribute)| =708396002 |Deoxyribonucleic acid of Plasmodium falciparum (substance)|, 370129005 |Measurement method (attribute)|=444077007 |Analysis using reverse transcriptase polymerase chain reaction technique (procedure)|)} | 637 (8%) |