What Is a CPT Code? A Patient's Guide to Medical Billing Codes

Every medical procedure, test, and office visit is assigned a numeric code for billing purposes. The most common system is the Current Procedural Terminology (CPT) code set, maintained by the American Medical Association. There are roughly 10,000 CPT codes covering everything from a basic office visit (99213) to a complex robotic prostatectomy (55867).

When your doctor bills your insurance company, they submit a claim with CPT codes describing exactly what was done. Your insurer uses those codes to determine how much to pay the provider. This makes CPT codes the universal currency of medical billing — the same code means the same procedure at any hospital in the country.

Most CPT codes are five-digit numbers organized into categories. Codes in the 10000–69999 range cover surgical procedures. The 70000s cover radiology (X-rays, MRI, CT scans). The 80000–89999 range covers laboratory tests. Codes in the 90000–99999 range cover medicine and evaluation/management (like office visits).

There are also HCPCS codes (Healthcare Common Procedure Coding System), which are used by Medicare and Medicaid for services CPT doesn't cover — like ambulance rides, durable medical equipment, and certain drugs. HCPCS codes are alphanumeric (a letter followed by four digits), such as J0585 for botulinum toxin injections.

CPT codes make price comparison possible. Without them, "knee surgery" could mean a minor scope or a full replacement — and comparing prices would be meaningless. When you know the specific CPT code for your procedure, you can search for it across hospitals and get apples-to-apples comparisons.

Always ask your doctor or surgeon for the CPT code before any scheduled procedure. This is standard information that should be readily available. If your provider doesn't know or can't give you the code, ask them to check with their billing department. Once you have it, you can use My Health Price or call hospitals directly to compare prices.

The easiest way is to ask your ordering physician: "What CPT code will you use to bill this procedure?" For surgeries, the surgical consent form or pre-op paperwork sometimes lists the procedure codes. Your insurer's prior authorization confirmation letter often includes CPT codes as well.

You can also search by procedure description on My Health Price — our database matches common procedure names to their CPT codes. Alternatively, the CMS website and various medical billing resources publish searchable CPT code databases, though the full AMA code set requires a license to access.

A single visit or procedure often generates multiple CPT codes — and multiple charges. A knee arthroscopy might bill separately for the scope itself, any repair work done during the scope, anesthesia, the facility fee, and the surgeon's professional fee. Understanding that one procedure can produce five or six line items on a bill helps you review charges more accurately.

When reviewing an itemized bill, match each line item to the corresponding CPT code and ask your provider to explain any code you don't recognize. Services that weren't discussed or authorized before your procedure are worth questioning — they may be errors or unnecessary add-ons.