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C93.12 ICD-10-CM Code: Chronic myelomonocytic leukemia, in relapse

C93.12 maps to CMS-HCC V28 20 (RAF 1.136). Documentation must support MEAT. MEAT criteria · RAF calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

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

C93.12

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

Chronic myelomonocytic leukemia, in relapse

A chronic blood cancer affecting monocyte and myeloid cells that has returned or progressed after a period of control.

Buddy the Bee presenting code insight

Buddy Insight

Chronic myelomonocytic leukemia in relapse indicates disease recurrence or progression after a period of treatment response.

CMS-HCC V28

HCC 20

RAF 1.136

CMS-HCC V24

HCC 9

RAF 1.024

ACA/HHS

HCC 9

Varies by metal level

ESRD/PACE

HCC 9

RAF 0.181

RXHCC

HCC 19

RAF 1.949

Code Book Path

Official
C93Monocytic leukemia
C93.1Chronic myelomonocytic leukemia
C93.12Chronic myelomonocytic leukemia, in relapse

Inclusion Terms

Official
  • Chronic monocytic leukemia
  • CMML-1
  • CMML-2
  • CMML with eosinophilia

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C93.12 in this effective period.

Related Child Codes

Official
C93.10Chronic myelomonocytic leukemia not having achieved remission
C93.11Chronic myelomonocytic leukemia, in remission

Includes

Official

ICD-10-CM does not list Includes notes for C93.12 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C93.12 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C93.12 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C93.12 in this effective period.

Code Also

Official
  • , if applicable, eosinophilia (D72.18)

Buddy Documentation Tip

HCC Buddy guidance
Documentation must confirm prior remission with subsequent disease recurrence, including laboratory evidence of worsening monocytosis or cytopenias.
If transformation to acute leukemia has occurred, this should be clearly stated as it changes the code assignment.
Current treatment plan and blast percentage should be documented.

MEAT Support

HCC Buddy guidance
Documentation must confirm prior remission with subsequent disease recurrence, including laboratory evidence of worsening monocytosis or cytopenias.
If transformation to acute leukemia has occurred, this should be clearly stated as it changes the code assignment.
Current treatment plan and blast percentage should be documented.

Audit Caution

HCC Buddy guidance
Distinguish between true disease relapse and disease progression or transformation.
If monocyte counts gradually rise but never reached remission criteria, this is not relapse but rather persistent disease (C93.10).
Document whether the relapse involves blast transformation, as this fundamentally changes management.

Common Mistakes

HCC Buddy guidance
C93.10 (not achieved remission) applies to primary treatment failure, not relapse. If disease has transformed to acute leukemia, reclassify to the appropriate C93.0
code. C92.12 (chronic myeloid leukemia, in relapse) is a genetically distinct disease (BCR-ABL1 positive).

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 C93.12 an HCC code?

Yes. C93.12 (Chronic myelomonocytic leukemia, in relapse) maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24), with a community non-dual aged RAF of 1.136. It is billable for payment year 2026.

Coder answer: C93.12 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C93.12
Description
Chronic myelomonocytic leukemia, in relapse
HCC (V28)
HCC 20 — Lung and Other Severe Cancers
RAF
1.136
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers
1.136
V24HCC 9, Lung and Other Severe Cancers
1.024
ESRDHCC 9, Lung and Other Severe Cancers
0.181
RxHCCHCC 19, Lymphoma and Other Cancers
1.949

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 C93.12 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C93.12

For C93.12 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 C93.12 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C93.12 is the ICD-10-CM diagnosis code for chronic myelomonocytic leukemia, in relapse. A chronic blood cancer affecting monocyte and myeloid cells that has returned or progressed after a period of control. C93.12 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, C93.12 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 1.136. Under the older V24 model, C93.12 mapped to the same category but with a base RAF weight of 1.024, 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.

The '2' suffix indicates relapse or progression; distinguish between true relapse and disease progression in chronic disease. Because C93.12 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 C93.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •The '2' suffix indicates relapse or progression; distinguish between true relapse and disease progression in chronic disease
  • •Document whether the patient is experiencing transformation to acute leukemia, which changes the clinical picture

Clinical Significance

Chronic myelomonocytic leukemia in relapse indicates disease recurrence or progression after a period of treatment response. Relapse in chronic myelomonocytic leukemia may present as rising monocyte counts, worsening cytopenias, or transformation to acute myeloid leukemia, each requiring different therapeutic approaches.

Documentation Requirements

  • ✓Documentation must confirm prior remission with subsequent disease recurrence, including laboratory evidence of worsening monocytosis or cytopenias.
  • ✓If transformation to acute leukemia has occurred, this should be clearly stated as it changes the code assignment.
  • ✓Current treatment plan and blast percentage should be documented.

Commonly Confused Codes

  • •C93.10 (not achieved remission) applies to primary treatment failure, not relapse. If disease has transformed to acute leukemia, reclassify to the appropriate C93.0
  • •code. C92.12 (chronic myeloid leukemia, in relapse) is a genetically distinct disease (BCR-ABL1 positive).

Child Codes

C93.10Chronic myelomonocytic leukemia not having achieved remission
HCC 20
C93.11Chronic myelomonocytic leukemia, in remission
HCC 20
C93.12Chronic myelomonocytic leukemia, in relapse
HCC 20

Code Hierarchy

└C93Monocytic leukemia└C93.1Chronic myelomonocytic leukemia└C93.12Chronic myelomonocytic leukemia, in relapse
└C93.12Chronic myelomonocytic leukemia, in relapse

Because C93.12 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.

C93.12 maps to CMS-HCC V28 category 20, Lung and Other Severe Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. Because C93.12 carries a payment HCC, you can see what it adds to a RAF score and check the documentation the chart needs before it is submitted.

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