Inappropriate primary diagnosis

According to ICD-10-CM guidelines for coding and reporting, it is inappropriate to bill certain diagnosis codes as a primary or first listed diagnosis. Instead, these codes should always be sequenced as a secondary or subsequent diagnosis. Effective for claims processed on or after March 2, 2024, Anthem will apply these correct coding ICD-10-CM guidelines and deny:

• Professional claims submitted on a CMS-1500 form that report inappropriate primary diagnosis codes as the only diagnosis on the claim or claim line; and facility claims submitted on a CMS‑1450 form that report inappropriate primary diagnosis codes as the principal diagnosis or only code on the claim.

As provided by ICD-10-CM guidelines, inappropriate primary diagnosis codes include but are not limited to:

• External Cause Codes of Morbidity (V, W, X, or Y codes ICD-10-CM): Describes an environmental event causing an injury, not the nature of the injury, and therefore should not be used as a principal diagnosis. These codes are intended to be supplemental to the principal or primary diagnosis code indicating the nature of the condition. In addition, based on this guideline, a diagnosis code of external causes cannot be the only diagnosis on the claim.
• Manifestation Codes: Certain conditions contain both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD Manual coding guidelines have established a coding convention that requires the underlying condition to be sequenced first followed by the manifestation. According to the ICD Manual coding guidelines, the primary, first listed, or principal diagnosis cannot be a manifestation code. In addition, based on this guideline, a manifestation code cannot be the only diagnosis on the claim.
• Sequela Codes: A sequela (7th character S) code cannot be listed as the primary, first listed, or principal diagnosis on a claim. Coding of a sequela requires reporting of the condition or nature of the sequela sequenced first, followed by the sequela (7th character S) code. In addition, based on this guideline, a sequela (7th character S) code cannot be the only diagnosis on a claim.
• Secondary Diagnosis: According to ICD guidelines, a secondary diagnosis code can only be used as a secondary diagnosis. Since these codes are only for use as supplemental codes, any procedure or service received with a secondary diagnosis code as the principal or primary diagnosis will be denied as incorrectly coded.

• EOB Message: We denied this service since it was reported incorrectly. Per CMS (Federal) correct coding guidelines, specific supplementary classification ICD-10 codes cannot be used as the primary diagnosis or as the only diagnosis on the claim.

Ex-Codes: 00V16 and v16

If you have questions about this communication or need assistance, contact Provider Services at:

• Hoosier Healthwise: 806-408-6132
• Healthy Indiana Plan: 844-533-1995
• Hoosier Care Connect: 844-284-1798