B20 ICD-10-CM Code: Human immunodeficiency virus [HIV] disease
B20 maps to CMS-HCC V28 1. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Human immunodeficiency virus [HIV] disease (B20)
B20
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHuman immunodeficiency virus [HIV] disease
This code represents a diagnosis of HIV (human immunodeficiency virus) disease, which is a viral infection that attacks the immune system and can progress to AIDS if untreated. It is used to document that a patient has been diagnosed with HIV infection.
Buddy Insight
Human immunodeficiency virus disease is one of the most significant codes in risk adjustment, carrying its own dedicated HCC category (HCC 1) across all models.
CMS-HCC V28
MappedHCC 1
Coefficient HCC 1: 0.301 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 001
Code-level coefficient reference
ESRD/PACE
MappedHCC 1
Code-level coefficient reference
RXHCC
MappedHCC 1
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for B20. Check the code and parent instructions in the Code Book.
Excludes 2
Official- carrier or suspected carrier of infectious disease (Z22.-)Inherited from A00-B99
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)Inherited from A00-B99
- infectious and parasitic diseases specific to the perinatal period (P35-P39)Inherited from A00-B99
- influenza and other acute respiratory infections (J00-J22)Inherited from A00-B99
Related Codes
No related codes are included in this display for B20. Check the Code Book for the complete code path.
Includes
Official- acquired immune deficiency syndrome [AIDS]
- AIDS-related complex [ARC]
- HIV infection, symptomatic
- diseases generally recognized as communicable or transmissibleInherited from A00-B99
Excludes 1
Official- asymptomatic human immunodeficiency virus [HIV] infection status (Z21)
- exposure to HIV virus (Z20.6)
- inconclusive serologic evidence of HIV (R75)
- certain localized infections - see body system-related chaptersInherited from A00-B99
Code First
Official- Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-)
Use Additional
Official- code(s) to identify all manifestations of HIV infection
- code to identify resistance to antimicrobial drugs (Z16.-)Inherited from A00-B99
Code Also
OfficialNo Code Also instructions are included in this display for B20. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 B20 an HCC code?
Yes. B20 (Human immunodeficiency virus [HIV] disease) maps to HCC 1, HIV/AIDS under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.301. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: B20 is billable and maps to V28 HCC 1, HIV/AIDS. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- B20
- Description
- Human immunodeficiency virus [HIV] disease
- HCC (V28)
- HCC 1 — HIV/AIDS
- RAF reference coefficient
- 0.301
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work B20 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for B20
For B20, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
B20 is the ICD-10-CM diagnosis code for human immunodeficiency virus [hiv] disease. This code represents a diagnosis of HIV (human immunodeficiency virus) disease, which is a viral infection that attacks the immune system and can progress to AIDS if untreated. It is used to document that a patient has been diagnosed with HIV infection. B20 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering human immunodeficiency virus [hiv] disease (b20).
Under the CMS-HCC V28 risk adjustment model, B20 maps to HIV/AIDS (HCC 1) with a source-labeled community, non-dual, aged reference coefficient of 0.301. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Human immunodeficiency virus disease, HIV infection with any clinical manifestation or AIDS-defining condition. Per ICD-10-CM convention, B20 is used for confirmed HIV disease with any clinical evidence of immunodeficiency. For B20, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for B20 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Human immunodeficiency virus disease, HIV infection with any clinical manifestation or AIDS-defining condition. Per ICD-10-CM convention, B20 is used for confirmed HIV disease with any clinical evidence of immunodeficiency.
- •Do not use B20 for asymptomatic HIV (use Z21). The distinction hinges on clinical manifestations, opportunistic infections, AIDS-defining illness, or provider-documented HIV disease all support B20.
- •HIV disease is durable HCC coding; once B20 is appropriate, the patient continues to qualify even during well-controlled therapy.
Clinical Significance
Human immunodeficiency virus disease is one of the most significant codes in risk adjustment, carrying its own dedicated HCC category (HCC 1) across all models. HIV disease requires lifelong antiretroviral therapy and monitoring, with substantial healthcare resource utilization. Accurate annual capture is essential as it must be reported each calendar year.
Documentation Requirements
- ✓Confirmed HIV diagnosis (positive HIV-1/2 antibody/antigen combination test with confirmatory testing)
- ✓CD4 count and viral load (HIV RNA quantitative) from current year
- ✓Current antiretroviral therapy regimen documented
- ✓Associated conditions: opportunistic infections, AIDS-defining illnesses
- ✓Provider assessment and plan addressing HIV management in current encounter
Includes
- acquired immune deficiency syndrome [AIDS]
- AIDS-related complex [ARC]
- HIV infection, symptomatic
Excludes 1, Do NOT code together
Use Additional Code
- code(s) to identify all manifestations of HIV infection
Code First
- Human immunodeficiency virus [HIV] disease complicating pregnancy, childbirth and the puerperium, if applicable (O98.7-)
Commonly Confused Codes
- •Z21 (Asymptomatic human immunodeficiency virus infection status): Used for patients with positive HIV test but NO symptoms or manifestations; B20 indicates active HIV disease
- •R75 (Inconclusive laboratory evidence of HIV): Inconclusive testing; do not code B20 without confirmed positive result
- •Z20.6 (Contact with and suspected exposure to HIV): Exposure risk only, no confirmed infection