What is ICD-10 code C81.90?

C81.90 is the ICD-10-CM diagnosis code for Hodgkin lymphoma, unspecified, unspecified site. Hodgkin lymphoma of an unspecified type affecting an unspecified location in the body. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C81.90 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C81.90 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. C81.90 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. C81.90 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 C81.90?

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 C81.90, V28 maps to Lymphoma and Other Cancers at RAF 0.671 while V24 mapped to Lymphoma and Other Cancers at RAF 0.675. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C81.90?

This is a less specific code; use only when the subtype and/or site cannot be determined from documentation Query the provider if more specific information is available to allow for more precise coding Because C81.90 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 C81.90: Hodgkin lymphoma

ICD-10-CM Code View

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Code lookupC81.90Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C81.90

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

Hodgkin lymphoma, unspecified, unspecified site

Hodgkin lymphoma of an unspecified type affecting an unspecified location in the body.

Buddy Insight

Hodgkin lymphoma, unspecified type and unspecified site, is the least specific Hodgkin lymphoma code, lacking both histologic subtype and anatomic location details.

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

RAF 0.671

CMS-HCC V24

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.675

ACA/HHS

Mapped

HCC 12

HHS-HCC 12

Varies by metal level

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.111

RXHCC

Mapped

HCC 21

Hodgkin Lymphoma and Other Ca...

RAF 0.410

Code Book Path

Official

C81Hodgkin lymphoma

C81.9Hodgkin lymphoma, unspecified

C81.90Hodgkin lymphoma, unspecified, unspecified site

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C81.90 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C81.90 in this effective period.

Related Child Codes

Official

C81.91Hodgkin lymphoma, unspecified, lymph nodes of head, face, and neck

C81.92Hodgkin lymphoma, unspecified, intrathoracic lymph nodes

C81.93Hodgkin lymphoma, unspecified, intra-abdominal lymph nodes

C81.94Hodgkin lymphoma, unspecified, lymph nodes of axilla and upper limb

C81.95Hodgkin lymphoma, unspecified, lymph nodes of inguinal region and lower limb

Includes

Official

ICD-10-CM does not list Includes notes for C81.90 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C81.90 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C81.90 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C81.90 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C81.90 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Definitive diagnosis of Hodgkin lymphoma (not merely suspected)

Documentation explaining why subtype and site are not specified (e.g., awaiting pathology, outside records incomplete)

Plan to obtain more specific diagnostic information when possible

Provider assessment confirming the diagnosis during the encounter

MEAT Support

HCC Buddy guidance

Definitive diagnosis of Hodgkin lymphoma (not merely suspected)

Documentation explaining why subtype and site are not specified (e.g., awaiting pathology, outside records incomplete)

Plan to obtain more specific diagnostic information when possible

Provider assessment confirming the diagnosis during the encounter

Audit Caution

HCC Buddy guidance

Using C81.90 as a permanent code when pathology and imaging eventually provide more specific information

Not querying the provider for subtype and site when staging workup has been completed

Coding C81.90 for suspected but unconfirmed Hodgkin lymphoma — a definitive diagnosis is required

Failing to update the code after biopsy results and staging are finalized

Common Mistakes

HCC Buddy guidance

C81.70 — Other Hodgkin lymphoma, unspecified site: use C81.70 when pathology classifies the variant as 'other'; use C81.90 when the subtype is truly undetermined

C85.90 — Non-Hodgkin lymphoma, unspecified: ensure the lymphoma is confirmed as Hodgkin type

D47.Z9 — Other specified neoplasms of uncertain behavior of lymphoid tissue: use when the diagnosis is not yet confirmed as malignant

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 C81.90 an HCC code?

Yes. C81.90 (Hodgkin lymphoma, unspecified, unspecified site) maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24), with a community non-dual aged RAF of 0.671. It is billable for payment year 2026.

Coder answer: C81.90 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C81.90
Description: Hodgkin lymphoma, unspecified, unspecified site
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

V24HCC 10, Lymphoma and Other Cancers

0.675

ESRDHCC 10, Lymphoma and Other Cancers

0.111

RxHCCHCC 21, Hodgkin Lymphoma and Other Cancers

0.410

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 C81.90 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C81.90

For C81.90 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 C81.90 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C81.90 is the ICD-10-CM diagnosis code for hodgkin lymphoma, unspecified, unspecified site. Hodgkin lymphoma of an unspecified type affecting an unspecified location in the body. C81.90 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).

Under the CMS-HCC V28 risk adjustment model, C81.90 maps to Lymphoma and Other Cancers (HCC 21) with a community, non-dual, aged base RAF weight of 0.671. Under the older V24 model, C81.90 mapped to the same category but with a base RAF weight of 0.675, 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.

This is a less specific code; use only when the subtype and/or site cannot be determined from documentation. Because C81.90 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 C81.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a less specific code; use only when the subtype and/or site cannot be determined from documentation
•Query the provider if more specific information is available to allow for more precise coding

Clinical Significance

Hodgkin lymphoma, unspecified type and unspecified site, is the least specific Hodgkin lymphoma code, lacking both histologic subtype and anatomic location details. This code is typically used when a definitive Hodgkin diagnosis exists but pathology subtype or staging workup has not yet been completed or is unavailable. It remains HCC-relevant but should be updated when more specific information becomes available.

Documentation Requirements

✓Definitive diagnosis of Hodgkin lymphoma (not merely suspected)
✓Documentation explaining why subtype and site are not specified (e.g., awaiting pathology, outside records incomplete)
✓Plan to obtain more specific diagnostic information when possible
✓Provider assessment confirming the diagnosis during the encounter
✓Treatment status documentation

Commonly Confused Codes

•C81.70: Other Hodgkin lymphoma, unspecified site: use C81.70 when pathology classifies the variant as 'other'; use C81.90 when the subtype is truly undetermined
•C85.90: Non-Hodgkin lymphoma, unspecified: ensure the lymphoma is confirmed as Hodgkin type
•D47.Z9: Other specified neoplasms of uncertain behavior of lymphoid tissue: use when the diagnosis is not yet confirmed as malignant