ICD-10 Code

Also called: Diagnosis Code, International Classification of Diseases

In plain English

A standardized code that describes your diagnosis or reason for the medical visit. ICD-10 codes start with a letter followed by numbers (like J06.9 for upper respiratory infection). These are different from CPT codes, which describe what was done.

Real-world example

You visit the doctor for a sore throat. The diagnosis code might be J02.9 (acute pharyngitis). This code gets paired with the CPT code for the office visit (99213) on your insurance claim.

Why this matters for your bill

Wrong diagnosis codes can cause insurance denials or make a covered service appear uncovered. If a claim is denied, check whether the ICD-10 code accurately reflects your condition — an incorrect code is a common and fixable error.

Confused by your bill?

Upload your bill and we'll explain every charge in plain English — no medical degree required.

Analyze My Bill — $10

$10 one-time payment · No subscription · Money-back guarantee

Related billing terms

Allowed Amount

The maximum amount your insurance company will pay for a specific medical service. If your provider ...

Balance Billing

When an out-of-network provider bills you for the difference between their charge and what your insu...

Coinsurance

The percentage of costs you pay for a covered medical service after you've met your deductible. For ...

Copay (Copayment)

A fixed dollar amount you pay for a covered medical service at the time you receive it. Unlike coins...