Searching the ICD-9-CM Indices 101

Helpful hints from Career Step's AHIMA-approved medical coding course on searching the ICD-9-CM indices.
For medical billing and coding professionals, proficiency in using the ICD-9-CM Alphabetic Index to Diseases, Index to External Causes and Alphabetic Index to Procedures is essential to consistent and accurate coding. Understanding how these indices are set up will make it easier and faster to find the correct codes. The points outlined below will hopefully help improve your proficiency in using the indices found in the ICD-9-CM.

The Indices Are Alphabetized and Use Main Terms and Sub-terms.
The indices contain main terms in bold font and listed in alphabetical order. Under each main term are found indented, applicable sub-terms, sub-subterms etc., which are also listed in alphabetical order.

The indices move from general to specific and use indentation to indicate increasing levels of specificity.

In general, the indices work from a general level to a more specific level, with another level of specificity being achieved with each level of indentation to the right. The sub-terms below the main terms are used to describe or modify the main term. The sub-subterms found below the sub-terms are used to describe or modify the sub-terms and so on.

For example, let’s look at how to use the Alphabetic Index to Diseases to find the code for the diagnosis of chronic kidney disease.

We start with the main term disease, because this is the most general or broadest term found in our diagnosis. Once we locate the main term disease in the index, we check to see if there are specific sub-terms from our diagnosis listed below the main term that will help us assign a more specific code. So, we ask ourselves, “What kind of disease am I trying to code?” Well, the diagnosis tells us that the disease we are coding for is kidney disease, so we review the sub-terms until we find a sub-term for kidney. Now, we need to determine if we should stop here and assign code 593.9 or decide if our diagnosis contains any information about the type of kidney disease we are coding for that can be used to assign an even more specific diagnosis. The diagnosis tells us that the kidney disease is chronic in nature, so we need to look to see if there is a sub-subterm for chronic, and lo and behold, there is one! Now, the index still has more sub-terms that are indented further down, but we have run out of terms from our diagnostic statement, so we cannot proceed to a further level of specificity.

We have gone as far as we can, and the index directs us to assign code 585.9. In the index itself a condensed version of our example would look something like this:

Disease, Diseased
  Kidney 593.9
  chronic 585.9

However, we are not done yet. A good coder knows that they must always go to the tabular list to verify the code that they were directed to by the index. When we check code 585.9 in the tabular list we find the diagnoses listed under that code include chronic renal (kidney) disease, which is an exact match for our diagnosis.

Instructional Notes Lead Coders in the Right Direction.
There are a few types of instructional notes found in the indices. Generally, these notes instruct the coder to see some other part of the index to find the right terms that lead to the code they are looking for. There is one instructional note in particular that seems to give many students some trouble—the instructional note that says “see condition.” This instructional note is usually found next to a main term that identifies a body site. It is not directing the coder to look under the main term, condition; rather, this instructional note is directing the coder to look under the main term for the condition that is affecting that particular anatomic site. Let’s refer back to our diagnosis of chronic kidney disease for an example. If we try to use the term kidney as a main term, when we look it up we will find that there is an instructional note that says –see condition. We can’t get a code for chronic kidney disease by starting with kidney as a main term, so we have to follow the instructional note and try searching for a main term for the condition that is affecting the patient’s kidney. In this case the condition is simply disease, and we know that if we use this as a main term we can find an appropriate code to report for our diagnosis.

Take it to the Limit.
One of the biggest mistakes that new coders make in using the indices is that they don’t look far enough or dig deep enough. Remember, if using one main term does not yield a good result then you should try using another term from the documentation for your starting point. Additionally, you should review the available sub-terms for greater levels of specificity based on the diagnostic statement you are coding. You may also find that there are times when what seems like an obvious sub-term may not be used in the index, or the string of sub-terms you are using may not include the specificity that is needed to report your diagnosis. In those cases you may have to individually review each of the sub-terms listed under the main term to find the right trail that leads to the code you are looking for.

Practice Makes Perfect. Pay Attention to Detail.
I know this is advice no one wants to hear but everyone knows is true. Wouldn’t it be great if everything came to us naturally with no expenditure of effort on our part? Unfortunately, learning to find codes in the indices is just like any other skill you want to develop, and doing so will require practice. You will find that as you continue to practice the process for finding the correct codes will become easier and quicker. Additionally, keep in mind that paying close attention to detail will increase your successful location of the appropriate codes and cut down on the amount of time you spend in fruitless searching.

Cari Greenwood
CS Coding Support

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