> ## Documentation Index
> Fetch the complete documentation index at: https://docs.medera.info/llms.txt
> Use this file to discover all available pages before exploring further.

# Clinical RAG Overview

> Hybrid retrieval over clinical knowledge

(`ai-services/services/rag/advanced_clinical_rag.py`) runs hybrid semantic + lexical retriever retrieval over medical ontologies, clinical guidelines, drug interactions, and payer-specific PA rules.

## Components

* **Semantic:** `embedding model` embeddings + vector index

* **Keyword:** Custom lexical retriever index

* **Query rewriting:** `ClinicalQueryRewriter` for clinical context-aware reformulation

* **Ontology expansion:** SNOMED-CT, ICD-10, RxNorm

## Confidence bands

| Band        | Range   |
| :---------- | :------ |
| `VERY_HIGH` | ≥ 0.95  |
| `HIGH`      | ≥ 0.85  |
| `MODERATE`  | ≥ 0.70  |
| `LOW`       | ≥ 0.50  |
| `VERY_LOW`  | \< 0.50 |