Master ICD-10-CM Codes by the Chapter Letters

ICD-10-CM codes by the chaper letters
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Discover the ultimate approach to mastering ICD-10-CM codes by the chapter letters effortlessly! 

Are you aware that you can easily navigate through ICD-10-CM by using the chapter letters as your guide? With a total of 74,044 codes effective October 1, 2023, an increase of 395 codes from FY 2023, it’s practically impossible to memorize them all.

However, there is a brilliant strategy to put you in the right direction. In this article, I will share the secrets of mastering ICD-10-CM codes with ease, utilizing the chapter letters as your invaluable tool. As an added bonus, I’ll provide you with a phenomenal cheat sheet for quick reference, making your journey toward code proficiency an absolute joy. 

Prepare to be amazed by how effortlessly you’ll navigate the complexities of ICD-10-CM with this amazing approach!

Coincidentally, in a previous post, I highlighted the coding changes for FY 2024 that will take effect on October 1, 2023, and will be valid through September 30, 2024, according to the Centers for Medicare & Medicaid Services (CMS).

ICD-10-CM Codes and Mnemonics

While medical coders can’t realistically memorize all the ICD-10-CM codes, a helpful technique can get you close. It’s called mnemonics. Mnemonics is a strategy to help improve memory and learn crucial information.

Here’s how it works: In ICD-10-CM, the first digit of each code is an alpha character. With mnemonics, you can associate the first letter of a diagnosis code with the corresponding ICD-10-CM chapter. This not only simplifies the process of finding the initial letter of an ICD-10-CM code but also speeds it up significantly.

Mastering these mnemonics becomes even more critical considering the time sensitivity during medical coding exams. 

To assist you in this effort, I have created an ICD-10-CM Chapter Cheat Sheet, which you can easily access by signing up below.

ICD-10-CM Chapters and Mnemonics for Code Identification

The International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) is organized into 22 chapters for FY 2024. These chapters cover a wide range of medical conditions, and each code within ICD-10-CM begins with a letter. Understanding the chapters and their associated mnemonics can help you quickly identify the appropriate chapter for a given code.

masting ICD-10-CM by the chapter letters requires knowing the 22 chapters

Here are some essential points to remember about ICD-10-CM codes:

  1. Chapter Organization: Each chapter in ICD-10-CM is represented by a specific letter range, from A00 to Z99. The codes within these chapters pertain to related medical conditions and diseases.
  2. Multiple Letters for Some Chapters: Some chapters are denoted by more than one letter. For example, Chapter 1 covers Certain Infectious and Parasitic Diseases, with codes in ranges A00 to B99.
  3. Shared Beginning Letters: A few chapters share the same beginning letters. For instance, Chapters 2 and 3 both start with “D.” Chapter 2 covers Neoplasms (C00-D49), and Chapter 3 focuses on Diseases of the Blood and Blood-Forming Organs (D50-D89).

Using Mnemonics for Code Identification

To make it easier to remember the chapters, ICD-10-CM provides mnemonics for each chapter. Here are some examples to demonstrate how mnemonics can help you identify the first letter of a code and its corresponding chapter:

Example #1:

Chapter 9, Diseases of the Circulatory System (I00-I99), has the mnemonic “Infarction.” Think of myocardial infarction or heart attack related to the circulatory system. Any code starting with “I” indicates a circulatory system-related condition.

Example #2:

Chapter 4, Endocrine, Nutritional and Metabolic Diseases (E00-E89), has the mnemonic “Endocrine.” If you encounter code E11.65, the first letter “E” tells you it relates to the endocrine system. Looking up E11.65, you’ll find Type 2 diabetes mellitus with hyperglycemia.

Example #3:

For Chapter 5, Mental, Behavioral, and Neurodevelopmental Disorders (F01-F99), the mnemonic is “Feelings of hopelessness.” So, if a patient is diagnosed with persistent depressive disorder, you can anticipate the first letter of the code to be “F.” And indeed, looking it up as F34.1 confirms the code for Dysthymic disorder.

Downloading the ICD-10-CM Chapter Cheat Sheet

To access a comprehensive list of all the mnemonics for ICD-10-CM chapters, download the free cheat sheet provided through the signup form. With this resource, you’ll be better equipped to master the codes by their chapter letters, making the coding process more straightforward and efficient.

That’s not all! After you have reviewed this information and downloaded the chapter cheat sheet, be sure and take the short quiz to find out if you are a true ICD-10-CM Medical Coding Expert!

master ICD-10-CM by the chapter letters
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      1. Hi Marcheri,

        I understand that it can be hard to retain new information, especially when there may be a lot coming at you at once. Some things that have helped me, no matter what I’ve been learning, are to try to pick a designated place in my home that is quiet without distractions and I only focus on one topic at a time; study at a time of day or night that I am my sharpest (if my schedule allows); take notes and write things in my own words to help retain it better; take plenty of breaks; get plenty of sleep.

        Depending on your learning style, you may prefer to read and see images, listen to others explain, or you may prefer to learn by doing hands-on activities. I am a combination of all of these, so I appreciate a variety of ways to learn and retain information.

        As far as specific tips as they relate to your medical coding education, I would say the main thing is to know your coding guidelines and know where to find the information in your coding manuals. You can’t memorize everything. Tab your books, write any notes in the margins, and use highlighters to emphasize the important information.

        I kind of looked at my manuals like my bible when I was learning and preparing for the certification exam. And practice, practice, practice. Apply what you have learned to as many coding quizzes as you can take.

        When you do sit for the certification exam, remember it is timed. You are not expected to code as you would do in a real-world situation. You will be given multiple-choice questions.

        As an example, a coding scenario reads that a patient has been diagnosed with external hemorrhoids, and the choices are A) K64.4; B) J44.9; C) J18.9; D) K64.1, K57.30. If we know our chapters based on the first letter, we know that we can quickly eliminate B and C because those two codes are located in the respiratory system chapter (think “J” for junk in the lungs), and codes for hemorrhoids are located in the digestive system chapter (think “K” for Kaopectate).

        I hope this helps.

        1. My suggestion is to use flash cards,also my best time to study was alway just before I went to sleep because you can sleep on what study. It always helped me.

          1. Hey Teresa. Great suggestions. Flashcards always helped me too, and going to sleep with things fresh may work for a lot of people too.

            Thank you for your great feedback.

          1. Lisa, there is no particular way you have to tab your books. It really is a matter of preference. But just make sure that you use plastic tabs and not paper tabs, because paper tabs are not allowed during the certification exam. The purpose of the tabs is to help you find the information quickly during the exam, so know your books inside and out. Add pre-printed tabs or create your own. Some people prefer to add the tabs to the right-hand side of the pages, some like to add them to the top or bottom of the pages, and some use a combination of placement. So do whatever you feel most comfortable with. I used some on the sides and some on the top. Also, I found that using too many tabs would just slow me down, so be somewhat strategic about it. Between the tabs and highlighting certain information that I knew I would need to know on the exam really helped. Good luck on the exam!

  1. Do you have any suggestions for specific things that we should include in the notes inside our ICD-10-CM manual? Do you have a list for that also? That is something that I would be very interested in.

    1. Hi Cheryl,

      It would be difficult for me to list here specifically what all I wrote in my manuals to prepare for the CPC exam. However, at the time, I enrolled in CCO’s (CertificationCoachingOrg) Review Blitz course. It not only taught me how to bubble and highlight in my manuals, but it also included the types of notes to add throughout. I recommend their course without hesitation.

        1. Pamela, I currently have the AAPC coding manual for ICD-10-CM, but there are others. They will all give you this same information. The course you are taking now probably has a particular manual they are using that you will need to buy. I would check with them. As far as sitting for the CPC certification exam, you are allowed to bring the ICD-10-CM coding manual of your choice, but you want to have the current year.

  2. Thank you so much for this! I am starting all over again and learning this coding and billing is fun but alot of information! This really helped me! You’re awesome!

    1. Hi Pamela.

      You are so welcome! I’m glad it’s helping you. There is a lot to learn in this field, for sure. I think that’s why you have to really love it to stick with it.

      Have a great night!

  3. This is really helpful Debbie. You are right knowing Mnemonics, helps you save a lot of your time coding.

  4. Thanks for the updates!!!…I’m a newbie,currently studying to take CPC early 2021.I appreciate all the information that will help me pass.

  5. hi debbie i am new for coding how to find correct code from chart please explain simple method

    thanks & regards,

    1. Hi Chiranjeevi,

      I provided some examples in my post on how to determine the right Chapter where the code would be found. To find the exact code, however, you would need to look it up in the Alphabetic Index first and then verify it in the Tabular List. I hope this helps.

  6. Hi Debbie Jones,

    I am studying the Text book 21 Chapters of ICD-10. It is 730 pages, so many information. How can i memorize? How can I study it fast? especially the theory.

    1. Hi Alex,
      I don’t think there is a fast way to study ICD-10-CM, but I’ll try to tell you some things to focus on based on what I did. Read the first pages in the coding manual. Know the code structure; the layout of the manual and chapter structure; key words, medical terms, and abbreviations related to ICD-10-CM coding; coding guidelines and conventions; and the process for looking up and verifying main terms and subterms. Highlight important details in your manual. Practice (and practice some more) abstracting pertinent information from provider’s documentation and assign the correct codes in the right sequence. Doing this over and over is what will help you learn and code quicker. I hope this helps.

  7. Hello! I am in a HIT program and currently learning ICD-10-CM coding, with PCS to come! I would love all the help I can get. Currently scouring the internet for little “Cheat sheets” I can use to quickly remind myself of the Guidelines (esp for things like Sepsis and HIV/AIDS).

    1. I hope you found the ICD-10-CM Chapter Cheat Sheet helpful. If you put terms like Sepsis and HIV/AIDS in the search box on my site, you will find some information on these topics that you may also find useful. Good luck to you!

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