C95.00
BillableAcute leukemia of unspecified cell type not having achieved remission
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C95.00 an HCC code?
Yes. C95.00 maps to Metastatic Cancer to Peritoneum and Other Specified Sites under the CMS-HCC V28 risk adjustment model (and Metastatic Cancer and Acute Leukemia 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 C95.00
For C95.00 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 C95.00 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C95.00 is the ICD-10-CM diagnosis code for acute leukemia of unspecified cell type not having achieved remission. An acute leukemia of unknown cell type that has not responded to treatment or achieved remission. C95.00 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, C95.00 maps to Metastatic Cancer to Peritoneum and Other Specified Sites (HCC 18) with a community, non-dual, aged base RAF weight of 0.368. Under the older CMS-HCC V24 model, C95.00 maps to Metastatic Cancer and Acute Leukemia (HCC 8) with a community, non-dual, aged base RAF weight of 2.484. 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 when the specific cell type cannot be determined; review pathology and flow cytometry results to see if a more specific code applies. Because C95.00 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 C95.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use when the specific cell type cannot be determined; review pathology and flow cytometry results to see if a more specific code applies
- •The fifth character '0' indicates active disease without remission status
Clinical Significance
Acute leukemia of unspecified cell type not having achieved remission is used when an acute leukemia is confirmed but the specific cell lineage (myeloid, lymphoid, or other) has not been determined. This typically occurs early in the diagnostic workup, in resource-limited settings, or when the leukemia defies standard phenotypic classification.
Documentation Requirements
- ✓Documentation should explain why cell type classification was not achieved and list the diagnostic studies performed or pending (flow cytometry, cytogenetics, molecular testing).
- ✓The acute nature must be confirmed by blast count or clinical presentation.
- ✓Treatment response confirming no remission must be documented.