C93.90
BillableMonocytic leukemia, unspecified, not having achieved remission
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C93.90 an HCC code?
Yes. C93.90 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24).
HCC Category Mapping
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 C93.90
For C93.90to 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 C93.90 during that encounter — not just copy-forwarded from a problem list.
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 community, non-dual, aged base RAF weight of 1.136. Under the older V24 model, C93.90 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.
Use this code when monocytic leukemia type cannot be further specified; review pathology reports for more specific classification. Because C93.90 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 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.