One of the biggest mistakes new medical coders make is finding a code in the Alphabetic Index and stopping there.

Remember:

📖 The Index helps you FIND the possible code.

✅ The Tabular List helps you VERIFY the correct code.

Diagnosis coding matters because ICD-10-CM codes explain why a service was medically necessary. Choosing the correct code requires more than matching words—you must also understand the instructions, conventions, and sequencing rules.

I always advise to move guidelines to the codes so you do not have to go to the guidelines and codes during the exam.