Question 1

What is ICD-10 code C83.00?

Accepted Answer

C83.00 is the ICD-10-CM diagnosis code for Small cell B-cell lymphoma, unspecified site. A type of cancer of the lymph system (small cell B-cell lymphoma) with no specific lymph node location identified. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C83.00 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C83.00 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.

Question 2

Is C83.00 an HCC code?

Accepted Answer

Yes. The final FY2026 CMS mapping file maps C83.00 to HCC 21 (Lymphoma and Other Cancers) under CMS-HCC V28 with source-labeled reference coefficients HCC 21 0.671.  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.

Question 3

Is C83.00 billable?

Accepted Answer

Yes. C83.00 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. C83.00 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.

Question 4

Which HCC does C83.00 map to under V28?

Accepted Answer

C83.00 maps to CMS-HCC V28 HCC 21 (Lymphoma and Other Cancers).  The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

Question 5

What RAF reference is published for C83.00?

Accepted Answer

C83.00 has source-labeled community, non-dual, aged reference coefficients HCC 21 0.671 under CMS-HCC V28 for payment year 2026.  The coefficients come from the CMS V28 relative-factor file. 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.

Question 6

What is the V28 vs V24 difference for C83.00?

Accepted Answer

For C83.00, the current CMS-HCC V28 result is HCC 21 (Lymphoma and Other Cancers). Select a historical effective period before comparing a V24 mapping.  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.

Question 7

What documentation supports C83.00?

Accepted Answer

This is a less specific code; attempt to identify the primary site of involvement from imaging or pathology reports If a specific site is documented, use codes C83.01-C83.05 or C83.06-C83.09 for greater specificity For C83.00, 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. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. One mnemonic element does not establish that a diagnosis is reportable.

Question 8

Can C83.00 be a primary diagnosis?

Accepted Answer

Yes. C83.00 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Question 9

Which codes cannot be reported with C83.00?

Accepted Answer

The Excludes1 note that applies to C83.00 lists personal history of non-Hodgkin lymphoma (Z85.72); chronic lymphocytic leukemia (C91.1); mature T/NK-cell lymphomas (C84.-); Waldenström macroglobulinemia (C88.00). An Excludes1 condition is not reported together with C83.00; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists Kaposi's sarcoma of lymph nodes (C46.3); secondary and unspecified neoplasm of lymph nodes (C77.-); secondary neoplasm of bone marrow (C79.52); secondary neoplasm of spleen (C78.89); those are separate conditions that may be reported together with C83.00 when both are documented.

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C83.00 ICD-10-CM Code: Small cell B-cell lymphoma, unspecified site

HCC Buddy Code Card

C83.00

Is C83.00 an HCC code?

HCC Category Mapping

MEAT review for C83.00

Get the V28 mapping + MEAT cheat sheet

What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

Also searched as

Work C83.00 in HCC Buddy