Coding Standards
ICD-10-CM
The U.S. clinical modification of WHO ICD-10, maintained by NCHS and CMS for diagnosis coding on all U.S. healthcare claims.
Definition
ICD-10-CM ("Clinical Modification") is the U.S. variant of the World Health Organization's ICD-10 classification, expanded for U.S. clinical and billing needs. NCHS maintains the diagnosis side (CM) and CMS maintains the procedure side (PCS, used only on inpatient hospital claims). Updates are published annually with an effective date of October 1.
ICD-10-CM has roughly 70,000 codes (vs. WHO ICD-10's roughly 14,000) and adds U.S.-specific concepts like full laterality, expanded injury codes (S/T chapter), and Z codes for social determinants of health. It is mandatory for HIPAA-covered entities for all diagnosis coding on claims, including outpatient, professional, and most inpatient claims.
ICD-10-CM is distinct from WHO ICD-10 (the international parent) and from ICD-11 (the WHO successor that some U.S. payers and EHRs are beginning to adopt). AutoICD's primary coding endpoint returns ICD-10-CM by default; ICD-11 is opt-in via the include_icd11 flag.
When to use
- •Any U.S. health claim, encounter record, or risk-adjustment submission.
- •Building a U.S.-facing clinical product, EHR, or payer integration.
- •Cross-walking from ICD-9 legacy data, ICD-11, or WHO ICD-10 into a U.S. context.
Try it in AutoICD API
Code clinical text to ICD-10-CM
curl -X POST https://autoicdapi.com/v1/code \
-H "Authorization: Bearer $AUTOICD_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"text": "55F with type 2 diabetes mellitus, hypertension, and hyperlipidemia."
}'Language: bash. View full API docs · Get an API key.