ICD-9 Codes

ICD-9 codes will no longer be used unless you are billing a claim that incurred prior to 10/1/15.  But because these codes are so critical to the history of coding, no insurance manual will be complete without at least some mention of these codes.

So what is an ICD-9 code anyway?

ICD-9, International Classification of Diseases - Ninth Revision, is the coding system that is used to provide a written description of a patient’s disease, illness, injury, symptoms or complaints and translate it from the word format into an ICD-9 code. ICD-9 booklet is updated by the AMA (American Medical Association) on a yearly basis.

ICD-9 codes are three digit, four digit and five digit codes that are listed in the ICD- 9 manual with code sets that range from 001.0 through V82.9.

 ICD-9 codes are required on all claims with a date of service prior to 10/1/15. 

These codes tell the health insurance carrier everything about the patient’s encounter. So even though they were not present when the patient was seen they are able to determine exactly why the patient was being treated.

This starts with careful, detailed documentation of every aspect of the patient’s reason for the visit:

  • The patient’s complaints.
  • When the complaints started.
  • Duration
  • Severity 
  • What they were doing when it occurred.
  • If they had it before.

This documentation is what will be used to determine which of the hundreds of ICD-9 codes are appropriate to use.  

ICD-9 codes are entered in field 21 of the CMS 1500 claim form

ICD-9 codes are broken down in the following way:

3 digits represent the category:

  • 250 -  Diabetes

4 digits represent the subcategory:

  • 250.1   Diabetes with ketoacidosis

5 digits represent the sub classification:

  • 250.13  Diabetes with ketoacidosis, type I [juvenile type], uncontrolled

Claims should always be coded to the highest level of specificity. This means that a 3 digit code should be used only if no valid 4 digit codes are available. A four digit code should be used only if no valid 5 digit is available. If a valid 5 digit is available, it should always be used. Each digit addition within the code tells you more about the condition.

What’s Changed?

  • The new codes are alpha numeric codes.
  • The code changed from five positions to seven.
  • 13,000 codes under ICD-9 to 68,000 codes under ICD-10.
  • ICD-10 has been expanded to fully describe the condition/disease/injury.
  • Codes were added to reflect which side of the body.
  • Codes were added to reflect the patient’s trimester of pregnancy.
  • It expanded the system so we would not run out of codes.
  • The new codes would allow for more in depth review of disease and treatments to improve the outcomes.

The impact of changing from ICD-9 to 10 codes continues to be felt. Providers are complaining about the complexity of the new codes and a lot of providers continue to use the crosswalk, which basically takes the old ICD-9 code and points them toward the exact same ICD-10 match.

The goal of the new ICD-10 codes was simply not to replace the old with a new look alike code. It was changed to obtain a clearer more precise diagnosis. Given a chance, the ICD-10 codes will provide a lot more data that will help us key into better ways to track outcomes and treat patients.


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