Medical Billing Codes Explained
Those codes on your medical bill actually matter. CPT codes determine what you're charged for, and wrong codes mean wrong prices. Here's how to read them and spot problems.
Types of Billing Codes
CPT Codes (Current Procedural Terminology)
Five-digit codes that describe medical procedures and services. These directly determine what you're charged. Example: 99213 is a mid-level office visit, 99215 is a high-complexity visit — and the price difference can be hundreds of dollars.
ICD-10 Codes (Diagnosis Codes)
These describe your diagnosis. They matter because insurance coverage depends on the diagnosis matching the procedure. Wrong diagnosis codes can lead to claim denials.
HCPCS Codes
Used for supplies, equipment, and services not covered by CPT codes. These often show up as facility charges.
What Is Upcoding?
Upcoding is when a provider bills for a more expensive service than what was actually performed — like billing a level 5 office visit when it was really a level 3. It's one of the most common billing errors.