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C93.90 ICD-10-CM Code: Monocytic leukemia, unspecified, not having achieved remission

C93.90 maps to CMS-HCC V28 20. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

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Code lookupC93.90

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

C93.90

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

Monocytic leukemia, unspecified, not having achieved remission

A blood cancer affecting monocytes (a type of white blood cell) where the specific type is not identified and the cancer has not responded to treatment.

Buddy the Bee presenting code insight

Buddy Insight

Monocytic leukemia, unspecified, not having achieved remission, is used when the specific type of monocytic leukemia (acute, chronic, juvenile, or other) cannot be determined from available documentation.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 20

Coefficient HCC 20: 1.136 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 009

Code-level coefficient reference

ESRD/PACE

HCC 9

Code-level coefficient reference

RXHCC

HCC 19

Code-level coefficient reference

Code Book Path

Official
C93Monocytic leukemiaC93.9Monocytic leukemia, unspecifiedC93.90Monocytic leukemia, unspecified, not having achieved remission

Inclusion Terms

Official
  • Monocytic leukemia, unspecified with failed remission
  • Monocytic leukemia, unspecified NOS

Excludes 2

Official
  • Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
  • secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
  • secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
  • secondary neoplasm of spleen (C78.89)Inherited from C81-C96

Related Codes

Official
C93.91Monocytic leukemia, unspecified in remissionC93.92Monocytic leukemia, unspecified in relapse

Includes

Official
  • monocytoid leukemiaInherited from C93

Excludes 1

Official
  • personal history of leukemia (Z85.6)Inherited from C93

Code First

Official

No Code First sequencing instructions are included in this display for C93.90. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C93.90. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C93.90. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Documentation should state the monocytic nature of the leukemia and that remission has not been achieved.
Every effort should be made to obtain pathology, flow cytometry, or molecular studies to classify the specific subtype.
The reason for unspecified status (e.g., incomplete workup, pending results) should be noted.

MEAT Support

HCC Buddy guidance
Documentation should state the monocytic nature of the leukemia and that remission has not been achieved.
Every effort should be made to obtain pathology, flow cytometry, or molecular studies to classify the specific subtype.
The reason for unspecified status (e.g., incomplete workup, pending results) should be noted.

Audit Caution

HCC Buddy guidance
This unspecified code should be a last resort
query the provider for additional specificity whenever possible. Using this code when a more specific code applies may result in audit findings. Ensure the monocytic lineage is actually documented rather than assumed from clinical presentation.

Common Mistakes

HCC Buddy guidance
C93.00 (acute monoblastic/monocytic leukemia), C93.10 (chronic myelomonocytic leukemia), and C93.30 (juvenile myelomonocytic leukemia) are all more specific alternatives that should be used when documentation supports them.
C95.90 (leukemia, unspecified) is even less specific and should be avoided when monocytic lineage is known.

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 C93.90 an HCC code?

Yes. C93.90 (Monocytic leukemia, unspecified, not having achieved remission) maps to HCC 20, Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.136. 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. It is billable for payment year 2026.

Coder answer: C93.90 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
C93.90
Description
Monocytic leukemia, unspecified, not having achieved remission
HCC (V28)
HCC 20 — Lung and Other Severe Cancers
RAF reference coefficient
1.136
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers
1.136
ESRDHCC 9, Lung and Other Severe Cancers
Not separately weighted
RxHCCHCC 19, Leukemias and Other Hematologic Cancers
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C93.90 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C93.90

For C93.90, 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.

  • 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

Coder workflow notes

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What This Code Means

C93.90 is the ICD-10-CM diagnosis code for monocytic leukemia, unspecified, not having achieved remission. A blood cancer affecting monocytes (a type of white blood cell) where the specific type is not identified and the cancer has not responded to treatment. C93.90 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, C93.90 maps to Lung and Other Severe Cancers (HCC 20) with a source-labeled community, non-dual, aged reference coefficient of 1.136. No V24 mapping is shown for C93.90; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. 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.

Use this code when monocytic leukemia type cannot be further specified; review pathology reports for more specific classification. For C93.90, 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. 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, source-labeled coefficient references, and MEAT documentation criteria for C93.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code when monocytic leukemia type cannot be further specified; review pathology reports for more specific classification
  • •The fifth character '0' indicates no remission; verify treatment response status in documentation

Clinical Significance

Monocytic leukemia, unspecified, not having achieved remission, is used when the specific type of monocytic leukemia (acute, chronic, juvenile, or other) cannot be determined from available documentation. This code represents a less specific classification and should prompt review of pathology to assign a more precise code when possible.

Documentation Requirements

  • ✓Documentation should state the monocytic nature of the leukemia and that remission has not been achieved.
  • ✓Every effort should be made to obtain pathology, flow cytometry, or molecular studies to classify the specific subtype.
  • ✓The reason for unspecified status (e.g., incomplete workup, pending results) should be noted.

Commonly Confused Codes

  • •C93.00 (acute monoblastic/monocytic leukemia), C93.10 (chronic myelomonocytic leukemia), and C93.30 (juvenile myelomonocytic leukemia) are all more specific alternatives that should be used when documentation supports them.
  • •C95.90 (leukemia, unspecified) is even less specific and should be avoided when monocytic lineage is known.

Child Codes

C93.90Monocytic leukemia, unspecified, not having achieved remission
HCC 20
C93.91Monocytic leukemia, unspecified in remission
HCC 20
C93.92Monocytic leukemia, unspecified in relapse
HCC 20

Code Hierarchy

└C93Monocytic leukemia└C93.9Monocytic leukemia, unspecified└C93.90Monocytic leukemia, unspecified, not having achieved remission
└C93.90Monocytic leukemia, unspecified, not having achieved remission

Also searched as

  • C93 90
  • C9390

For C93.90, 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.

C93.90 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. The mapping identifies a payment HCC category for C93.90. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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