Inside Chat citations
How Lorraine Chat sources, ranks, and displays clinical evidence so a clinician can audit any claim in seconds. A short tour of the retrieval stack and the design decisions behind it.
- Written by
- Lorraine Team
- Role
- Engineering
- Published
- 10 April 2026
- Reading time
- 6 min read

Clinicians told us something simple: an uncited answer is worse than no answer. If they cannot trace a claim back to a source in a few seconds, they cannot use it. So we built citations as a first-class part of the Chat experience, not an afterthought.
What we index
Chat retrieves from a hybrid corpus: PubMed abstracts and open-access full text, the international guidance clinicians here actually reach for, including WHO material, and the South African guideline set that matters most in daily practice — the Standard Treatment Guidelines and Essential Medicines List, NDoH and NICD guidance, and the SAMJ. We keep the SA corpus in a separate index with a preference weight, so local guidance surfaces first when it is relevant.
How we rank
Retrieval is hybrid — keyword search alongside dense embeddings — followed by a clinician-tuned reranker that weights SA provenance, recency, and study design. For differential and management questions we favour structured guideline content; for drug dosing we favour the SA Essential Medicines List and trial-grade evidence.
How we display
Citations appear inline in the answer, each backed by a hover card with the source title, year, publication, and the relevant quote. A single click opens the source. Where Chat cannot ground a claim, it is built to say so — uncertainty is a first-class surface, not a silence.
We are still iterating. Next up: structured citation export you can attach to your own CPD record, and richer drug-monograph rendering for dose and interaction questions.
Written by
Lorraine Team
Engineering