Overview This endpoint identifies medical concepts that are semantically similar to a provided query or set of criteria. It leverages advanced machine learning models trained on medical terminology to discover related concepts that may not share exact keywords but are clinically relevant and contextually similar.
Request Body Primary search query or concept description to find similar concepts for
Target vocabularies to search within (array of strings) Examples : ["SNOMED", "ICD10CM"], ["RXNORM", "NDC"]
Clinical domains to focus the similarity search (array of strings) Examples : ["Condition", "Procedure"], ["Drug", "Device"]
Concept classes to include in similarity search (array of strings) Examples : ["Clinical Finding", "Procedure"], ["Ingredient", "Brand Name"]
Minimum similarity score threshold (0.1 to 1.0) Higher values = More strict similarity matching
Maximum number of similar concepts to return
Include similarity scores in the response
Include explanations for why concepts are considered similar
Filter to standard concepts only Options : S (standard), C (classification), N (non-standard)
Include invalid/deprecated concepts in similarity search
Similarity algorithm to use Options : semantic (embedding-based), lexical (text-based), hybrid (combined)
Response Indicates if the request was successful
Contains the similar concepts search results Array of concepts similar to the query Vocabulary-specific concept code
Source vocabulary identifier
Clinical domain classification
Similarity score between 0.0 and 1.0
Reason for similarity match (if requested)
Standard concept flag (S, C, or N)
Alternative names for the concept
Information about the similarity search The original search query provided
Similarity algorithm applied
Minimum similarity threshold applied
Total concepts evaluated for similarity
Number of similar concepts returned
Search processing time in milliseconds
curl -X POST "https://api.omophub.com/v1/search/similar" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "query": "type 2 diabetes mellitus", "vocabulary_ids": ["SNOMED", "ICD10CM"], "domain_ids": ["Condition"], "similarity_threshold": 0.8, "max_results": 10, "include_scores": true, "include_explanations": true, "standard_concept": "S" }'
{ "success" : true , "data" : { "similar_concepts" : [ { "concept_id" : 44054006 , "concept_name" : "Type 2 diabetes mellitus" , "concept_code" : "44054006" , "vocabulary_id" : "SNOMED" , "domain_id" : "Condition" , "concept_class_id" : "Clinical Finding" , "similarity_score" : 1.0 , "explanation" : "Exact match - same clinical concept" , "standard_concept" : "S" , "synonyms" : [ "Non-insulin dependent diabetes mellitus" , "Adult-onset diabetes" ] }, { "concept_id" : 201826 , "concept_name" : "Type 2 diabetes mellitus without complications" , "concept_code" : "E11.9" , "vocabulary_id" : "ICD10CM" , "domain_id" : "Condition" , "concept_class_id" : "4-char nonbill code" , "similarity_score" : 0.92 , "explanation" : "High similarity - more specific variant of the same condition" , "standard_concept" : "S" , "synonyms" : [ "Type II diabetes mellitus uncomplicated" ] }, { "concept_id" : 443729 , "concept_name" : "Diabetes mellitus type 2 with hyperglycemia" , "concept_code" : "443729" , "vocabulary_id" : "SNOMED" , "domain_id" : "Condition" , "concept_class_id" : "Clinical Finding" , "similarity_score" : 0.89 , "explanation" : "High similarity - related complication of the same condition" , "standard_concept" : "S" , "synonyms" : [ "Type 2 DM with elevated glucose" ] } ], "search_metadata" : { "original_query" : "type 2 diabetes mellitus" , "algorithm_used" : "hybrid" , "similarity_threshold" : 0.8 , "total_candidates" : 125000 , "results_returned" : 3 , "processing_time_ms" : 245 } } }
Usage Examples Basic Similarity Search Find concepts similar to a medical condition:
{ "query" : "hypertension" , "max_results" : 5 , "similarity_threshold" : 0.7 } Cross-Vocabulary Similarity Find similar concepts across multiple vocabularies:
{ "query" : "myocardial infarction" , "vocabulary_ids" : [ "SNOMED" , "ICD10CM" , "ICD9CM" ], "domain_ids" : [ "Condition" ], "similarity_threshold" : 0.8 , "include_explanations" : true } Pharmacological Similarity Find similar drug concepts with detailed scoring:
{ "query" : "metformin hydrochloride" , "vocabulary_ids" : [ "RXNORM" ], "domain_ids" : [ "Drug" ], "concept_class_ids" : [ "Ingredient" , "Clinical Drug" ], "similarity_threshold" : 0.75 , "include_scores" : true , "algorithm" : "semantic" } 
