A31.2

HCC Category Mapping

What This Code Means

A serious infection caused by mycobacterium avium-intracellulare bacteria that has spread throughout the body, most commonly occurring in people with weakened immune systems such as those with advanced HIV/AIDS. This infection affects multiple organ systems and requires prolonged antibiotic treatment.

Coding Tips

• •DMAC is typically an opportunistic infection in immunocompromised patients; always code the underlying immunodeficiency condition (such as B20 for HIV) as an additional diagnosis
• •Verify documentation specifies 'disseminated' status; localized MAC infections are coded differently (A31.0 or A31.1), so confirm the infection has spread beyond a single site

Clinical Significance

Disseminated Mycobacterium avium-intracellulare complex (DMAC) is a severe systemic infection occurring almost exclusively in profoundly immunocompromised patients, particularly those with AIDS and CD4 counts below 50. It is an AIDS-defining illness that significantly worsens prognosis and requires lifelong suppressive therapy unless immune reconstitution occurs.

Documentation Requirements

• ✓Blood culture or tissue biopsy positive for Mycobacterium avium complex (MAC)
• ✓Evidence of disseminated disease (involvement of 2+ organ systems: blood, bone marrow, liver, lymph nodes)
• ✓CD4 count documentation (typically below 50 cells/mm3 in HIV patients)
• ✓HIV/AIDS status with B20 coding when applicable
• ✓Treatment regimen documented (typically clarithromycin/azithromycin + ethambutol + rifabutin)

Commonly Confused Codes