Where can I look up what a code means?

Ask the billing office to describe any code you do not recognise, in plain words. For HCPCS Level II codes, the Centers for Medicare & Medicaid Services publishes the code list. Your insurer's explanation of benefits often describes the service too.

Why does the same service have two different codes?

A hospital bill can show a revenue code for the department and a CPT or HCPCS code for the service on the same line. They describe the same charge from two angles.

Medical billing codes explained (CPT, HCPCS, revenue codes)

What the numbers and letters on a medical bill mean, which ones describe the service, which describe the diagnosis, and which only tell you the department.

Last updated 2026-09-25

Codes are how providers and insurers describe care to each other. You do not need to learn them all, but knowing which kind you are looking at tells you what a line is about.

CPT codes: what was done

Five-character codes, usually five digits, that describe a procedure or service, such as an office visit, an X-ray or a lab test. They are maintained by the American Medical Association and appear on most doctor and hospital bills.

HCPCS Level II codes: supplies, drugs and extras

A letter followed by four digits. They cover things CPT does not, such as drugs given by injection, medical supplies, equipment and ambulance services. Codes starting with J are often drugs, and codes starting with E are durable medical equipment.

Revenue codes: which department

Four-digit codes on hospital bills that group charges by department. For example, 0250 is pharmacy, 0300 is laboratory, and 0450 is the emergency room. A revenue code on its own tells you where a charge came from, not exactly what was done.

Diagnosis codes: why it was done

ICD-10-CM codes, a letter followed by numbers, describe the diagnosis or reason for the visit. They matter for insurance: a wrong diagnosis code can be why a claim was denied.

Modifiers and drug codes

Modifiers are two characters added to a code, such as 25 or LT, that say something extra: a separate service on the same day, or which side of the body.
NDC numbers identify a specific drug and package, and sometimes appear next to pharmacy charges.

What to check

Every charged line should have a code. A line with no code, the same code twice on the same day, or a code for something you do not recognise is worth a question.

Open your bill in MedBillCheckup (it is read on your device and never uploaded) and we will list each line with its code, point out lines with no code or repeated codes, and write out what to ask.

Common questions

Where can I look up what a code means?: Ask the billing office to describe any code you do not recognise, in plain words. For HCPCS Level II codes, the Centers for Medicare & Medicaid Services publishes the code list. Your insurer's explanation of benefits often describes the service too.
Why does the same service have two different codes?: A hospital bill can show a revenue code for the department and a CPT or HCPCS code for the service on the same line. They describe the same charge from two angles.

Check your own bill

Open it in MedBillCheckup and your browser will read the charges (the bill never leaves your device), then run these checks for you and write out what to ask. Reading is free and needs no account.

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