What is ICD-10 code A31.2?

A31.2 is the ICD-10-CM diagnosis code for Disseminated mycobacterium avium-intracellulare complex (DMAC). It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). A31.2 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. A31.2 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. A31.2 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. A31.2 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does A31.2 map to under V28?

A31.2 maps to CMS-HCC V28 6 (Opportunistic Infections). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does A31.2 pay in RAF?

A31.2 carries a community, non-dual, aged (CNA) RAF weight of 0.381 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for A31.2?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For A31.2, V28 maps to Opportunistic Infections at RAF 0.381 while V24 mapped to Opportunistic Infections at RAF 0.424. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports A31.2?

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 Because A31.2 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM A31.2: Disseminated mycobacterium

A31.2 maps to CMS-HCC V28 6 (RAF 0.381). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupA31.2Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Other bacterial diseases (A30-A49)

A31.2

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Disseminated mycobacterium avium-intracellulare complex (DMAC)

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.

Buddy Insight

CMS-HCC V28

Mapped

HCC 6

Opportunistic Infections

RAF 0.381

CMS-HCC V24

Mapped

HCC 6

Opportunistic Infections

RAF 0.424

ACA/HHS

Mapped

HCC 6

HHS-HCC 6

Varies by metal level

ESRD/PACE

Mapped

HCC 6

Opportunistic Infections

RAF 0.076

RXHCC

Mapped

HCC 5

Opportunistic Infections

RAF 0.468

Code Book Path

Official

A31Infection due to other mycobacteria

A31.2Disseminated mycobacterium avium-intracellulare complex (DMAC)

Inclusion Terms

Official

MAC sepsis

Excludes 2

Official

leprosy (A30.-)
tuberculosis (A15-A19)

Related Child Codes

Official

A31.0Pulmonary mycobacterial infection

A31.1Cutaneous mycobacterial infection

A31.8Other mycobacterial infections

A31.9Mycobacterial infection, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for A31.2 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for A31.2 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for A31.2 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for A31.2 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for A31.2 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

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

MEAT Support

HCC Buddy guidance

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

Audit Caution

HCC Buddy guidance

In HIV/AIDS patients, sequence B20 first with A31.2 as an additional code for the opportunistic infection

Disseminated means involvement beyond a single organ — do not code A31.2 for pulmonary-only MAC disease

MAC prophylaxis in HIV patients (CD4 <50) does not warrant coding A31.2 — only code when active disease is diagnosed

Do not confuse with M. tuberculosis disseminated disease, which is coded under A19 series

Common Mistakes

HCC Buddy guidance

A31.0 (Pulmonary mycobacterial infection) — Use A31.0 for lung-only NTM disease; A31.2 is for disseminated (multi-organ) MAC disease

A15 series (Tuberculosis) — MAC is nontuberculous; completely different organism requiring different treatment

B20 (HIV disease) — Code B20 as the underlying condition with A31.2 as the manifestation in HIV/AIDS patients

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is A31.2 an HCC code?

Yes. A31.2 (Disseminated mycobacterium avium-intracellulare complex (DMAC)) maps to Opportunistic Infections under the CMS-HCC V28 risk adjustment model (and Opportunistic Infections under V24), with a community non-dual aged RAF of 0.381. It is billable for payment year 2026.

Coder answer: A31.2 is billable and maps to V28 HCC 6, Opportunistic Infections. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: A31.2
Description: Disseminated mycobacterium avium-intracellulare complex (DMAC)
HCC (V28): HCC 6 — Opportunistic Infections
RAF: 0.381
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 6, Opportunistic Infections

0.381

V24HCC 6, Opportunistic Infections

0.424

ESRDHCC 6, Opportunistic Infections

0.076

RxHCCHCC 5, Opportunistic Infections

0.468

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work A31.2 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for A31.2

For A31.2 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed A31.2 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 RAF + MEAT cheat sheet

One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

A31.2 is the ICD-10-CM diagnosis code for disseminated mycobacterium avium-intracellulare complex (dmac). 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. A31.2 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other bacterial diseases (a30-a49).

Under the CMS-HCC V28 risk adjustment model, A31.2 maps to Opportunistic Infections (HCC 6) with a community, non-dual, aged base RAF weight of 0.381. Under the older V24 model, A31.2 mapped to the same category but with a base RAF weight of 0.424, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

DMAC is typically an opportunistic infection in immunocompromised patients; always code the underlying immunodeficiency condition (such as B20 for HIV) as an additional diagnosis. Because A31.2 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A31.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

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

•A31.0 (Pulmonary mycobacterial infection): Use A31.0 for lung-only NTM disease; A31.2 is for disseminated (multi-organ) MAC disease
•A15 series (Tuberculosis): MAC is nontuberculous; completely different organism requiring different treatment
•B20 (HIV disease): Code B20 as the underlying condition with A31.2 as the manifestation in HIV/AIDS patients