What this is
Saturnity's Codebook is a free medical coding reference that pulls structured data straight from the Centers for Medicare & Medicaid Services (CMS) public datasets and lays it out in a way that is actually quick to navigate. There is no signup, no ads, no email gate, and no paywall.
What is inside
- ICD-10-CM diagnosis codes, full CMS-published descriptors, hierarchy by chapter and section.
- ICD-10-PCS inpatient procedure codes, full CMS-published descriptors.
- HCPCS Level II codes, with original plain-English explanations on each one.
- CPT short descriptors from the CMS Physician Fee Schedule, with original plain-English explanations.
- NCCI procedure-to-procedure edits showing which procedure codes conflict, the modifier rule, and the effective dates.
- LCD coverage references linking codes to the relevant Local Coverage Determination on the CMS Coverage Database.
What is NOT inside
The full AMA CPT long descriptors and AMA CPT guidelines are licensed commercial content. They are not in this tool. The short descriptors you do see are the public CMS-published versions. The longer explanations on procedure codes are written from scratch using general medical knowledge, with a similarity check against known AMA phrasing patterns to keep our wording independent.
CDT (dental) codes are also outside our scope and are filtered out of every LCD parse.
Why build this
Medical coding references are often paywalled, ad-saturated, or buried behind clunky portals. The actual underlying datasets are public. This tool is a friendly skin over those public datasets, designed for billers and curious patients who just want to look something up.
How it stays fresh
An automated process checks the CMS download URLs on a quarterly schedule, recomputes hashes, and rebuilds the database only when something has actually changed. The site shows the build date in every page footer. If a build has not run in 120 days, a banner appears warning that the data may be out of date.
How to give feedback
If you spot something wrong, the source attribution table on each code page links straight back to the CMS publication so you can verify it yourself. If our wording on a procedure code reads off, that is fixable. Reach out through the contact form on the main Saturnity's Tools site.
Tech notes for the curious
Static site, plain JS, JSON data shards. No backend, no analytics, no fingerprinting. Local storage holds your bookmarks, recent lookups, and theme preference. Everything else is fetched on demand from the static data directory.