What is ICD-10 code C82.00?

C82.00 is the ICD-10-CM diagnosis code for Follicular lymphoma grade I, unspecified site. A slow-growing type of lymphoma called follicular lymphoma grade I that is present but the specific location in the body is not documented. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C82.00 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C82.00 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. C82.00 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. C82.00 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 C82.00?

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 C82.00, V28 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors at RAF 0.545 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 C82.00?

Grade I indicates the lowest grade (most differentiated) follicular lymphoma If the site is documented, use a more specific code (C82.01-C82.05 or others) rather than the unspecified code Because C82.00 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.

C82.00 ICD-10 Code: Follicular lymphoma grade I

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 lookupC82.00Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C82.00

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

Follicular lymphoma grade I, unspecified site

A slow-growing type of lymphoma called follicular lymphoma grade I that is present but the specific location in the body is not documented.

Buddy Insight

Follicular lymphoma grade I is the most indolent form of follicular lymphoma, a slow-growing non-Hodgkin B-cell lymphoma.

CMS-HCC V28

Mapped

HCC 21

Breast, Prostate, Colorectal ...

RAF 0.545

CMS-HCC V24

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.675

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

RAF 0.0

RXHCC

Mapped

HCC 21

Hodgkin Lymphoma and Other Ca...

RAF 0.0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

C82Follicular lymphoma

C82.0Follicular lymphoma grade I

C82.00Follicular lymphoma grade I, unspecified site

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C82.00 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C82.00 in this effective period.

Related Child Codes

Official

C82.01Follicular lymphoma grade I, lymph nodes of head, face, and neck

C82.02Follicular lymphoma grade I, intrathoracic lymph nodes

C82.03Follicular lymphoma grade I, intra-abdominal lymph nodes

C82.04Follicular lymphoma grade I, lymph nodes of axilla and upper limb

C82.05Follicular lymphoma grade I, lymph nodes of inguinal region and lower limb

Includes

Official

ICD-10-CM does not list Includes notes for C82.00 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C82.00 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C82.00 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C82.00 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C82.00 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology report confirming follicular lymphoma with grade I classification (0-5 centroblasts per high-power field)

Query provider for anatomic site information to assign a more specific code than unspecified

Staging workup results (Ann Arbor staging)

Documentation of treatment approach: watch-and-wait versus active therapy

MEAT Support

HCC Buddy guidance

Pathology report confirming follicular lymphoma with grade I classification (0-5 centroblasts per high-power field)

Query provider for anatomic site information to assign a more specific code than unspecified

Staging workup results (Ann Arbor staging)

Documentation of treatment approach: watch-and-wait versus active therapy

Audit Caution

HCC Buddy guidance

Not distinguishing between follicular lymphoma grades I, II, and III — the grade must be obtained from pathology as it affects treatment approach

Using unspecified site when staging imaging identifies specific nodal or extranodal locations

Confusing follicular lymphoma grade I with marginal zone lymphoma or other indolent B-cell lymphomas that have different codes

Using a personal history code (Z85.72) when the patient is still under active surveillance for an incurable but indolent lymphoma — follicular lymphoma grade I rarely 'cures,' so the active code is typically appropriate indefinitely

Common Mistakes

HCC Buddy guidance

C82.10 — Follicular lymphoma grade II, unspecified site: grade II has 6-15 centroblasts per high-power field; this distinction is made on pathology and affects treatment decisions

C82.20 — Follicular lymphoma grade III, unspecified: grade III is more aggressive and may require different treatment; centroblast count exceeds 15 per high-power field

C81.40 — Lymphocyte-rich Hodgkin lymphoma, unspecified: Hodgkin lymphoma is a completely different entity; pathology shows Reed-Sternberg cells in Hodgkin but follicular architecture in follicular lymphoma

C83.10 — Mantle cell lymphoma, unspecified: another B-cell lymphoma with a different immunophenotype (cyclin D1+) and more aggressive clinical course

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C82.00 an HCC code?

Yes. C82.00 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).

HCC Category Mapping

V28HCC 21, Breast, Prostate, Colorectal and Other Cancers and Tumors

0.545

V24HCC 10, Lymphoma and Other Cancers

0.675

ESRDHCC 10, Lymphoma and Other Cancers

0.000

RxHCCHCC 21, Hodgkin Lymphoma and Other Cancers

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.

MEAT Criteria for C82.00

For C82.00to 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 C82.00 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

C82.00 is the ICD-10-CM diagnosis code for follicular lymphoma grade i, unspecified site. A slow-growing type of lymphoma called follicular lymphoma grade I that is present but the specific location in the body is not documented. C82.00 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, C82.00 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C82.00 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. 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.

Grade I indicates the lowest grade (most differentiated) follicular lymphoma. Because C82.00 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 C82.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Grade I indicates the lowest grade (most differentiated) follicular lymphoma
•If the site is documented, use a more specific code (C82.01-C82.05 or others) rather than the unspecified code

Clinical Significance

Follicular lymphoma grade I is the most indolent form of follicular lymphoma, a slow-growing non-Hodgkin B-cell lymphoma. Grade I indicates predominantly small cleaved cells (centrocytes) with fewer than 5 centroblasts per high-power field, carrying the best prognosis among follicular lymphoma grades. Despite its indolent nature, follicular lymphoma is generally considered incurable with standard therapy, requiring long-term monitoring and intermittent treatment over many years.

Documentation Requirements

✓Pathology report confirming follicular lymphoma with grade I classification (0-5 centroblasts per high-power field)
✓Query provider for anatomic site information to assign a more specific code than unspecified
✓Staging workup results (Ann Arbor staging)
✓Documentation of treatment approach: watch-and-wait versus active therapy
✓Flow cytometry or immunohistochemistry results confirming B-cell lineage (CD20+, CD10+, BCL-2+)

Commonly Confused Codes

•C82.10 — Follicular lymphoma grade II, unspecified site: grade II has 6-15 centroblasts per high-power field; this distinction is made on pathology and affects treatment decisions
•C82.20 — Follicular lymphoma grade III, unspecified: grade III is more aggressive and may require different treatment; centroblast count exceeds 15 per high-power field
•C81.40 — Lymphocyte-rich Hodgkin lymphoma, unspecified: Hodgkin lymphoma is a completely different entity; pathology shows Reed-Sternberg cells in Hodgkin but follicular architecture in follicular lymphoma
•C83.10 — Mantle cell lymphoma, unspecified: another B-cell lymphoma with a different immunophenotype (cyclin D1+) and more aggressive clinical course