What is ICD-10 code B48.8?

B48.8 is the ICD-10-CM diagnosis code for Other specified mycoses. A fungal infection caused by other specified fungi not classified elsewhere, such as uncommon or emerging fungal pathogens. It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). B48.8 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. B48.8 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. B48.8 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. B48.8 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.

What is the V28 vs V24 difference for B48.8?

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 B48.8, 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 should coders know when reporting B48.8?

Use this code only when the specific fungal organism doesn't fit other B48 categories Document the specific fungal organism identified in the medical record for clarity Because B48.8 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.

2026 ICD-10-CM B48.8: Other specified mycoses

ICD-10-CM Code View

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Code lookupB48.8Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Mycoses (B35-B49)

B48.8

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

Other specified mycoses

A fungal infection caused by other specified fungi not classified elsewhere, such as uncommon or emerging fungal pathogens.

Buddy Insight

Other specified mycoses is a residual category for documented fungal infections that do not have their own specific ICD-10-CM code.

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

B48Other mycoses, not elsewhere classified

B48.8Other specified mycoses

Inclusion Terms

Official

Adiaspiromycosis
Infection of tissue and organs by Alternaria
Infection of tissue and organs by Drechslera
Infection of tissue and organs by Fusarium
Infection of tissue and organs by saprophytic fungi NEC

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for B48.8 in this effective period.

Related Child Codes

Official

B48.0Lobomycosis

B48.1Rhinosporidiosis

B48.2Allescheriasis

B48.3Geotrichosis

B48.4Penicillosis

Includes

Official

ICD-10-CM does not list Includes notes for B48.8 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for B48.8 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for B48.8 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for B48.8 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for B48.8 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific fungal organism identified and documented in the medical record

Culture, histopathology, or molecular testing confirming the fungal species

Site of infection documented

Immunocompromised status documented when present

MEAT Support

HCC Buddy guidance

Specific fungal organism identified and documented in the medical record

Culture, histopathology, or molecular testing confirming the fungal species

Site of infection documented

Immunocompromised status documented when present

Audit Caution

HCC Buddy guidance

Using unspecified mycosis (B49) when the organism has been identified — B48.8 is the correct code for specified organisms without dedicated codes

Not checking whether the identified organism has a specific ICD-10-CM code before defaulting to B48.8

Failing to document the specific organism name, which reduces audit defensibility for this residual category code

Common Mistakes

HCC Buddy guidance

B49 (Unspecified mycosis) - use only when the organism is completely unidentified; B48.8 is for identified but non-classified organisms

B48.4 (Penicillosis) - Talaromyces marneffei has its own code; do not use B48.8

B44.89 (Other forms of aspergillosis) - Aspergillus infections go to the B44 family, not B48.8

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 B48.8 an HCC code?

Yes. B48.8 (Other specified mycoses) 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: B48.8 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: B48.8
Description: Other specified mycoses
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 B48.8 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for B48.8

For B48.8 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 B48.8 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

B48.8 is the ICD-10-CM diagnosis code for other specified mycoses. A fungal infection caused by other specified fungi not classified elsewhere, such as uncommon or emerging fungal pathogens. B48.8 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering mycoses (b35-b49).

Under the CMS-HCC V28 risk adjustment model, B48.8 maps to Opportunistic Infections (HCC 6) with a community, non-dual, aged base RAF weight of 0.381. Under the older V24 model, B48.8 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.

Use this code only when the specific fungal organism doesn't fit other B48 categories. Because B48.8 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 B48.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code only when the specific fungal organism doesn't fit other B48 categories
•Document the specific fungal organism identified in the medical record for clarity

Clinical Significance

Other specified mycoses is a residual category for documented fungal infections that do not have their own specific ICD-10-CM code. This includes rare organisms like Adiaspiromycosis, Fusarium infections, or other emerging fungal pathogens. Despite being a catch-all code, it maps to the high-value opportunistic infections HCC, reflecting the clinical significance of these unusual infections.

Documentation Requirements

✓Specific fungal organism identified and documented in the medical record
✓Culture, histopathology, or molecular testing confirming the fungal species
✓Site of infection documented
✓Immunocompromised status documented when present
✓Treatment regimen and clinical response documented

Commonly Confused Codes

•B49 (Unspecified mycosis) - use only when the organism is completely unidentified; B48.8 is for identified but non-classified organisms
•B48.4 (Penicillosis) - Talaromyces marneffei has its own code; do not use B48.8
•B44.89 (Other forms of aspergillosis) - Aspergillus infections go to the B44 family, not B48.8