> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://help.truemed.com/letters-of-medical-necessity-lm-ns/lmn-basics/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://help.truemed.com/_mcp/server.

# LMN Basics

## Docs

- [What is a Letter of Medical Necessity?](https://help.truemed.com/letters-of-medical-necessity-lm-ns/lmn-basics/what-is-an-lmn.md): Learn what a Letter of Medical Necessity is, why it's required for HSA/FSA purchases, how long it's valid, and how it works across merchants and subscriptions.
- [LMN Requirements](https://help.truemed.com/letters-of-medical-necessity-lm-ns/lmn-basics/lmn-requirements.md): What a valid Letter of Medical Necessity must contain, how Truemed's clinical process meets those standards, and what to check if your LMN is questioned by your HSA/FSA administrator.