This column clarifies current coding requirements for the reporting of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes as required by the Health Insurance Portability and Accountability Act (HIPAA).
How does HIPAA relate to diagnostic coding?
As required by HIPAA, the U.S. Secretary of Health and Human Services (HHS) published a rule designating ICD-9-CM and its Official ICD-9-CM Guidelines for Coding and Reporting as the approved code set for use in reporting diagnoses. This final rule requires the use of ICD-9-CM and its official coding and reporting guidelines by health plans (including Medicare).
Why are reimbursement claims being denied due to HIPAA?
Payers require providers to use ICD-9-CM diagnosis codes with the highest degree of accuracy and completeness or the "greatest degree of specificity" as is required by HIPAA. Therefore, a code is invalid-and may result in a denial-if it has not been coded to the full number of digits required for that particular code.
What does "greatest degree of specificity" mean?
It can mean providing an ICD-9-CM code carried to the 3rd, 4th, or 5th digit. According to Official ICD-9-CM Guidelines for Coding and Reporting, "Diagnosis and procedure codes are to be used at their highest number of digits available." Specifically, use a three-digit code only if there are no four- or five-digit codes within that code category. Use a four-digit code only if there are no five-digit codes for that category. Use a five-digit code when they exist in a code category
For example, if a provider submits a claim with the diagnosis 389.0 (conductive hearing loss), this claim may be rejected because the code category has 5th digit subclassifications. The most appropriate subclassification should be selected, which might be 389.01 (conductive hearing loss, external), 389.02 (conductive hearing loss, tympanic), or 389.03 (conductive hearing loss, middle ear).
What happens if fourth or fifth digits are not available for a diagnostic code?
When a fourth or fifth digit is not available, do not add fourth or fifth digits to valid three-digit codes (e.g., do not simply add zeroes to valid three-digit codes).
The ICD-9-Coding Manual indicates when a fourth or fifth digit is required and offers fifth-digit subclassifications for use with certain categories of codes. For example, if a provider submits a claim with a diagnosis of 299.0 (autistic disorder), which requires a fifth digit, they are instructed to add "0" for current or active state or "1 " for residual state.
May I still use NOS (not otherwise specified) codes?
Diagnostic codes that are marked NOS or "unspecified" indicate that there is insufficient information on the medical record to assign a more specific code. Use an NOS code only when you lack the information necessary to code to a more specific subcategory.
What if the payer requires fifth-digit coding and there is none?
Provide the payer with a copy of the Official ICD-9-CM Guidelines for Coding and Reporting [PDF]. The guidelines explicitly state, "Diagnosis and procedure codes are to be used at their highest number of digits available."