C93.Z2
BillableOther monocytic leukemia, in relapse
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C93.Z2 an HCC code?
Yes. C93.Z2 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.Z2
For C93.Z2to 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.Z2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C93.Z2 is the ICD-10-CM diagnosis code for other monocytic leukemia, in relapse. A monocytic blood cancer of a type other than the more common varieties, where the cancer has returned after a period of remission. C93.Z2 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.Z2 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, C93.Z2 mapped to the same category but with a base RAF weight of 0.973 — 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 'Z' indicates other specified monocytic leukemia; document the specific subtype if available. Because C93.Z2 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.Z2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The 'Z' indicates other specified monocytic leukemia; document the specific subtype if available
- •Verify that prior remission is documented before coding relapse
Clinical Significance
Other monocytic leukemia in relapse represents disease recurrence of a rare monocytic leukemia variant following prior remission. These relapsed atypical subtypes pose particular management challenges due to limited salvage therapy evidence and often require individualized treatment approaches.
Documentation Requirements
- ✓Documentation must confirm prior remission followed by recurrence, with specific evidence of disease return such as rising monocyte counts, reappearance of abnormal cells on blood smear, or bone marrow findings.
- ✓The atypical variant characteristics and salvage treatment approach should be documented.