Relative factors by segment
Each segment is a separate regression; the factor is added to the beneficiary's demographic factors and other categories, then normalized and reduced by the coding intensity adjustment before it meets the plan's base rate. A factor of 1.000 equals the expected cost of an average beneficiary.
| Segment | Model code | Relative factor |
|---|---|---|
| Community, non-dual, aged | CNA_HCC19 | 1.798 |
| Community, non-dual, disabled | CND_HCC19 | 1.989 |
| Community, full-benefit dual, aged | CFA_HCC19 | 1.563 |
| Community, full-benefit dual, disabled | CFD_HCC19 | 1.661 |
| Community, partial-benefit dual, aged | CPA_HCC19 | 1.520 |
| Community, partial-benefit dual, disabled | CPD_HCC19 | 1.554 |
| Long-term institutional | INS_HCC19 | 0.957 |
Hierarchy
Hierarchical condition categories pay only the most severe manifestation of a disease. When HCC 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) or HCC 18 (Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid) is also documented for the same beneficiary, HCC 19 is dropped from the score. When HCC 19 is present it drops HCC 20 (Lung and Other Severe Cancers), HCC 21 (Lymphoma and Other Cancers), HCC 22 (Bladder, Colorectal, and Other Cancers), HCC 23 (Prostate, Breast, and Other Cancers and Tumors), so documenting the less severe condition alongside it adds nothing to payment but still matters for the clinical record.
ICD-10-CM codes that map to HCC 19
68 codes map to this category in the PY2027 initial mapping, concentrated in the C84 (23), C90 (12), D46 (10), C91 (9), C86 (6), C45 (5) code families. Descriptions are the CMS mapping descriptions for the FY2026 code set; a code that is deleted or split in the October code update stays valid for dates of service before the change.
| ICD-10-CM | Description |
|---|---|
| C450 | Mesothelioma of pleura |
| C451 | Mesothelioma of peritoneum |
| C452 | Mesothelioma of pericardium |
| C457 | Mesothelioma of other sites |
| C459 | Mesothelioma, unspecified |
| C8440 | Peripheral T-cell lymphoma, not elsewhere classified, unspecified site |
| C8441 | Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neck |
| C8442 | Peripheral T-cell lymphoma, not elsewhere classified, intrathoracic lymph nodes |
| C8443 | Peripheral T-cell lymphoma, not elsewhere classified, intra-abdominal lymph nodes |
| C8444 | Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb |
| C8445 | Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of inguinal region and lower limb |
| C8446 | Peripheral T-cell lymphoma, not elsewhere classified, intrapelvic lymph nodes |
| C8447 | Peripheral T-cell lymphoma, not elsewhere classified, spleen |
| C8448 | Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of multiple sites |
| C8449 | Peripheral T-cell lymphoma, not elsewhere classified, extranodal and solid organ sites |
| C844A | Peripheral T-cell lymphoma, not elsewhere classified, in remission |
| C8470 | Anaplastic large cell lymphoma, ALK-negative, unspecified site |
| C8471 | Anaplastic large cell lymphoma, ALK-negative, lymph nodes of head, face, and neck |
| C8472 | Anaplastic large cell lymphoma, ALK-negative, intrathoracic lymph nodes |
| C8473 | Anaplastic large cell lymphoma, ALK-negative, intra-abdominal lymph nodes |
| C8474 | Anaplastic large cell lymphoma, ALK-negative, lymph nodes of axilla and upper limb |
| C8475 | Anaplastic large cell lymphoma, ALK-negative, lymph nodes of inguinal region and lower limb |
| C8476 | Anaplastic large cell lymphoma, ALK-negative, intrapelvic lymph nodes |
| C8477 | Anaplastic large cell lymphoma, ALK-negative, spleen |
| C8478 | Anaplastic large cell lymphoma, ALK-negative, lymph nodes of multiple sites |
| C8479 | Anaplastic large cell lymphoma, ALK-negative, extranodal and solid organ sites |
| C847A | Anaplastic large cell lymphoma, ALK-negative, breast |
| C847B | Anaplastic large cell lymphoma, ALK-negative, in remission |
| C8630 | Subcutaneous panniculitis-like T-cell lymphoma not having achieved remission |
| C8631 | Subcutaneous panniculitis-like T-cell lymphoma, in remission |
| C8640 | Blastic NK-cell lymphoma not having achieved remission |
| C8641 | Blastic NK-cell lymphoma, in remission |
| C8650 | Angioimmunoblastic T-cell lymphoma not having achieved remission |
| C8651 | Angioimmunoblastic T-cell lymphoma, in remission |
| C9000 | Multiple myeloma not having achieved remission |
| C9001 | Multiple myeloma in remission |
| C9002 | Multiple myeloma in relapse |
| C9010 | Plasma cell leukemia not having achieved remission |
| C9011 | Plasma cell leukemia in remission |
| C9012 | Plasma cell leukemia in relapse |
| C9020 | Extramedullary plasmacytoma not having achieved remission |
| C9021 | Extramedullary plasmacytoma in remission |
| C9022 | Extramedullary plasmacytoma in relapse |
| C9030 | Solitary plasmacytoma not having achieved remission |
| C9031 | Solitary plasmacytoma in remission |
| C9032 | Solitary plasmacytoma in relapse |
| C9130 | Prolymphocytic leukemia of B-cell type not having achieved remission |
| C9131 | Prolymphocytic leukemia of B-cell type, in remission |
| C9132 | Prolymphocytic leukemia of B-cell type, in relapse |
| C9150 | Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission |
| C9151 | Adult T-cell lymphoma/leukemia (HTLV-1-associated), in remission |
| C9152 | Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse |
| C9160 | Prolymphocytic leukemia of T-cell type not having achieved remission |
| C9161 | Prolymphocytic leukemia of T-cell type, in remission |
| C9162 | Prolymphocytic leukemia of T-cell type, in relapse |
| C946 | Myelodysplastic disease, not elsewhere classified |
| D460 | Refractory anemia without ring sideroblasts, so stated |
| D461 | Refractory anemia with ring sideroblasts |
| D4620 | Refractory anemia with excess of blasts, unspecified |
| D4621 | Refractory anemia with excess of blasts 1 |
| D464 | Refractory anemia, unspecified |
| D469 | Myelodysplastic syndrome, unspecified |
| D46A | Refractory cytopenia with multilineage dysplasia |
| D46B | Refractory cytopenia with multilineage dysplasia and ring sideroblasts |
| D46C | Myelodysplastic syndrome with isolated del(5q) chromosomal abnormality |
| D46Z | Other myelodysplastic syndromes |
| D474 | Osteomyelofibrosis |
| D7581 | Myelofibrosis |
Where these codes sat in the V22 model
The V28 recalibration renumbered and regrouped categories; this table shows which legacy V22 categories the same ICD-10 codes belonged to, which is the quickest way to reconcile a V22-era HCC gap list with the current model.
| V22 HCC | Codes |
|---|---|
| 10 | 41 |
| 9 | 14 |
| 46 | 12 |
| 48 | 1 |
Capturing and defending the category
A category counts for a payment year when a mapped diagnosis is documented at least once during the data collection year by an acceptable provider type at a face-to-face or audio-video encounter, and when the note shows the condition was monitored, evaluated, assessed or treated. Chronic conditions do not carry forward: a category that is not re-documented in the year drops out of the score, which is why annual wellness visits and problem-list reconciliation are where most recapture happens. Risk adjustment data validation audits sample enrollees and ask for the medical record behind each submitted category; an unsupported category is removed and, under the extrapolation rules, the error rate is applied across the contract. The QuickIntell risk adjustment product surfaces suspected and unsupported categories from the chart, and the HCC hub lists every V28 category with its factor and code count.
Frequently asked questions
Which ICD-10 codes map to HCC 19?
68 ICD-10-CM codes map to HCC 19 in the CMS PY2027 initial mapping, for example C450 Mesothelioma of pleura; C451 Mesothelioma of peritoneum; C452 Mesothelioma of pericardium; C457 Mesothelioma of other sites. The full list is on this page; a code counts only when it is documented at a face-to-face or video encounter in the data collection year and supported by the record.
How much does HCC 19 add to a risk score?
The V28 relative factor for HCC 19 is 1.798 for a community, non-dual, aged beneficiary, 1.563 for full-benefit dual aged, 1.989 for non-dual disabled and 0.957 for long-term institutional members. A factor of 1.000 equals the expected annual cost of an average beneficiary, so the category's share of the payment follows the plan's base rate for that segment.
Does HCC 19 count together with related categories?
No. Within a hierarchy only the most severe category is paid. HCC 19 is dropped when HCC 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) or HCC 18 (Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid) is also present, and it drops HCC 20, HCC 21, HCC 22, HCC 23 when it is present.
What has to be documented for HCC 19 to be valid?
The diagnosis must be recorded by an acceptable provider type during a face-to-face or audio-video encounter in the service year, with the note showing that the condition was monitored, evaluated, assessed or treated. Risk adjustment data validation audits recover payment for categories the record does not support, so the code on the claim and the assessment in the note must match.
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.
- ICD-10-CM to CMS-HCC V28 mappings, payment year 2027 initialVersion PY2027 initial ICD-10-CM mappings (dates of service 2026) · effective 2027-01-01 · file 2027 Initial ICD-10-CM Mappings.csvSHA-256 9c260b06d0dd2806…
- CMS-HCC V28 model software: labels, hierarchies and relative factorsVersion CMS-HCC V28 software V2826.115.T2 (PY2027 initial) · effective 2027-01-01 · file C2824T2N.csvSHA-256 20f38d537493b41c…
Disclaimer
Relative factors and mappings are reproduced from the CMS risk adjustment model files as an operational reference. Payment depends on the plan's base rate, normalization, the coding intensity adjustment and the enrollee's segment. Not legal, clinical or billing advice.