FAQ 1. What is ICD-9?

ICD-9-CM (International Classification of Diseases, 9th edition, Clinical Modification) is a set of codes used by physicians, hospitals, and allied health workers to indicate diagnosis for all patient encounters. The ICD-9-CM is the HIPAA transaction code set for diagnosis coding.

The current International Classification of Diseases can trace its roots back to the Bertillon Classification first published in 1893. Starting in 1900, experts met about every 10 years under the auspices of the French government to revise the classifications. The fifth revision was published just before World War II. The World Health Organization took over responsibility for ICD in 1946 with publication of ICD-6. The intended purpose of the ICD-9 diagnosis codes (Volume 1 and 2) is for statistical tracking of diseases. (Nothing more) Codes are added only when it can be demonstrated that it will help in the identification and monitoring of the disease.

The current edition in the United States for morbidity classification, ICD-9-CM, has been in use since 1979. The original intent for the diagnosis codes was for epidemiological and not billing functions, although in the US, the codes are used by payers for billing and reimbursement purposes.

ICD-9 diagnosis codes consist of 3-5 numeric characters representing illnesses and conditions, and alphanumeric E codes, describing external causes of injuries, poisonings, and adverse effects; and V codes describe factors influencing health status and contact with health services.

ICD-9-CM consists of three volumes. Physicians use Volumes 1 and 2 only to assign diagnosis codes. Physicians use Current Procedural Terminology (CPT), published by the American Medical Association, to report medical and surgical procedures and physician service codes, rather than Volume 3 of the ICD-9-CM codes. The 3rd Volume of ICD-9-CM is used by Hospitals for reporting inpatient procedures and resource utilization.

FAQ 2. What are the 2015 changes for ICD-9?

According to CMS, the last regular, annual updates to both ICD-9-CM and ICD-10 code sets were made on October 1, 2011.   On October 1, 2012, October 1, 2013, and October 1, 2014 there were only limited code updates to both the ICD-9-CM and ICD-10 code sets to capture new technologies and diseases as required by section 503(a) of Pub. L. 108-173.  On October 1, 2015, there will be only limited code updates to ICD-10 code sets to capture new technologies and diagnoses as required by section 503(a) of Pub. L. 108-173. There will be no updates to ICD-9-CM, as it will no longer be used for reporting. On October 1, 2016 (one year after implementation of ICD-10), regular updates to ICD-10 will begin.

FAQ 3.  When will I need to transition from ICD-9 to ICD-10?

The transition to ICD-10-CM/PCS will take place on October 1, 2015.  All users will transition on the same date.  If your program is covered by the Health Insurance Portability and Accountability Act (HIPAA) then transitioning to ICD-10 code sets is mandatory.

There are no ICD-9 procedure code changes planned for 2015.  The 2015 ICD-9 diagnosis code changes can be found on the CMS website at http://www.cms.gov/Medicare/Coding/ICD9ProviderDiagnosticCodes/codes.html.

FAQ 4. Are "unspecified" diagnosis codes permitted with ICD-9-CM?

A. Yes, these types of codes are permitted when a more specific diagnosis is not available at the time of the encounter. For example, if the patient is diagnosed with a pneumonia but the physician is not able to determine additional detail than "Pneumonia, organism unspecified" (486) is a permissible diagnosis. However, if the pneumonia was associated with aspiration of vomit (507.0) or Avian influenza (488.01), then those specific codes would be used. 

Specificity is of particular importance, for example, as to the location of an injury, abdominal, back or limb pain. A specific diagnosis should indicate if an injury was of the left/right forearm or upper arm or 3rd digit finger as opposed to non-specific term "arm" or "finger".

The [ICD] Official Guidelines for Coding and Reporting says:

Signs/symptoms and "unspecified" codes have acceptable, even necessary, uses. While specific diagnosis codes should be reported when they are supported by the available medical record documentation and clinical knowledge of the patient's health condition, there are instances when signs/symptoms or unspecified codes are the best choices for accurately reflecting the healthcare encounter. Each healthcare encounter should be coded to the level of certainty known for that encounter.

If a definitive diagnosis has not been established by the end of the encounter, it is appropriate to report codes for sign(s) and/or symptom(s) in lieu of a definitive diagnosis. When sufficient clinical information isn't known or available about a particular health condition to assign a more specific code, it is acceptable to report the appropriate "unspecified" code (e.g., a diagnosis of pneumonia has been determined, but not the specific type). Unspecified codes should be reported when they are the codes that most accurately reflect what is known about the patient's condition at the time of that particular encounter. It would be inappropriate to select a specific code that is not supported by the medical record documentation or conduct medically unnecessary diagnostic testing in order to determine a more specific code. (underline added)

This information was also published in Coding Clinic, Second Quarter 2013, pages 29-30.

Payers may need to be reminded, "Adherence to these guidelines when assigning ICD-9-CM diagnosis and procedure codes is required under the Health Insurance Portability and Accountability Act (HIPAA)."  (ICD-9-CM Official Guidelines for Coding and Reporting)

Last Updated 04/16/2015

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