Medical coding uses standardized code sets to document diagnoses, procedures, and services for billing and data tracking.
🔹 ICD-10-CM (Diagnosis Codes)
- Purpose: Identify patient conditions
- Format: 3–7 alphanumeric characters (e.g., E11.9 for Type 2 diabetes)
- Key Rule: Code to the highest specificity (avoid unspecified codes when possible)
- Source: CMS ICD-10 Manual
🔹 CPT® (Procedure Codes)
- Purpose: Report medical services and procedures
- Format: 5-digit numbers (e.g., 99213 for an office visit)
- Categories:
- Evaluation & Management (E/M)
- Surgery
- Diagnostics
- Source: AMA CPT® Network
🔹 HCPCS (Supplies & Services)
- Level I: Identical to CPT® (physician services)
- Level II: Covers drugs, supplies, and equipment (e.g., A4253 for glucose test strips)
- Used by: Medicare, Medicaid, and private insurers
- Source: CMS HCPCS Updates
🔹 Key Differences
| Code Set | Used For | Managed By |
| ICD-10-CM | Diagnoses | CMS/WHO |
| CPT® | Procedures | AMA |
| HCPCS | Supplies/drugs | CMS |
