Internal Medicine Coding Alert

Code 079.99 makes an easy switch, but payers might not reimburse.

When your physician currently diagnoses a viral infection without specifying details, you have one coding choice in 079.99 (Viral and chlamydial infection in conditions classified elsewhere and of unspecified site; Unspecified viral and chlamydial infections; Unspecified viral infection). This code can be used in two circumstances. First, it can be used as an additional code for the unspecified viral agent in diseases classified elsewhere. Second, it can be used to classify a virus infection of unspecified nature or site as a stand-alone diagnosis.

ICD-10 change: When your diagnosis system changes to ICD-10 next year, those circumstances will lead you to distinct codes. Thus, an unspecified virus that is causing a disease classified elsewhere in ICD-10 will require you to use B97.89 (Other viral agents as the cause of diseases classified elsewhere) as a secondary diagnosis to whatever ICD-10 code(s) represents the “diseases classified elsewhere.”  In the case of an unspecified viral infection that is, itself, the primary diagnosis, you will use B34.9 (Viral infection, unspecified).

Documentation: Physicians will need to be more detailed in their documentation of viral infections so you can assign a more specific diagnosis whenever possible. Some payers might not reimburse for “unspecified” codes, so the same might hold true with B97.89 and B34.9. The more detailed the physician’s documentation can be, the better your chances of correct coding and reimbursement. 

Coding tips: On your superbill and/or favorites in your EHR, after unspecified viral infection, list B34.9 and B97.89. Include notations about the expanded diagnosis family and the available options to prompt the physician to enter the necessary information.