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_HCC409 | 0.598 |
| Community, non-dual, disabled | CND_HCC409 | 0.562 |
| Community, full-benefit dual, aged | CFA_HCC409 | 0.799 |
| Community, full-benefit dual, disabled | CFD_HCC409 | 0.844 |
| Community, partial-benefit dual, aged | CPA_HCC409 | 0.604 |
| Community, partial-benefit dual, disabled | CPD_HCC409 | 0.623 |
| Long-term institutional | INS_HCC409 | 0.284 |
Hierarchy
Hierarchical condition categories pay only the most severe manifestation of a disease. When HCC 263 (Atherosclerosis of Arteries of the Extremities with Ulceration or Gangrene) or HCC 405 (Traumatic Amputations and Complications) is also documented for the same beneficiary, HCC 409 is dropped from the score.
ICD-10-CM codes that map to HCC 409
44 codes map to this category in the PY2027 initial mapping, concentrated in the T87 (18), Z89 (12), Z44 (9), Z97 (3), G54 (2) 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 |
|---|---|
| G546 | Phantom limb syndrome with pain |
| G547 | Phantom limb syndrome without pain |
| T8730 | Neuroma of amputation stump, unspecified extremity |
| T8731 | Neuroma of amputation stump, right upper extremity |
| T8732 | Neuroma of amputation stump, left upper extremity |
| T8733 | Neuroma of amputation stump, right lower extremity |
| T8734 | Neuroma of amputation stump, left lower extremity |
| T8740 | Infection of amputation stump, unspecified extremity |
| T8741 | Infection of amputation stump, right upper extremity |
| T8742 | Infection of amputation stump, left upper extremity |
| T8743 | Infection of amputation stump, right lower extremity |
| T8744 | Infection of amputation stump, left lower extremity |
| T8750 | Necrosis of amputation stump, unspecified extremity |
| T8751 | Necrosis of amputation stump, right upper extremity |
| T8752 | Necrosis of amputation stump, left upper extremity |
| T8753 | Necrosis of amputation stump, right lower extremity |
| T8754 | Necrosis of amputation stump, left lower extremity |
| T8781 | Dehiscence of amputation stump |
| T8789 | Other complications of amputation stump |
| T879 | Unspecified complications of amputation stump |
| Z44101 | Encounter for fitting and adjustment of unspecified right artificial leg |
| Z44102 | Encounter for fitting and adjustment of unspecified left artificial leg |
| Z44109 | Encounter for fitting and adjustment of unspecified artificial leg, unspecified leg |
| Z44111 | Encounter for fitting and adjustment of complete right artificial leg |
| Z44112 | Encounter for fitting and adjustment of complete left artificial leg |
| Z44119 | Encounter for fitting and adjustment of complete artificial leg, unspecified leg |
| Z44121 | Encounter for fitting and adjustment of partial artificial right leg |
| Z44122 | Encounter for fitting and adjustment of partial artificial left leg |
| Z44129 | Encounter for fitting and adjustment of partial artificial leg, unspecified leg |
| Z89431 | Acquired absence of right foot |
| Z89432 | Acquired absence of left foot |
| Z89439 | Acquired absence of unspecified foot |
| Z89441 | Acquired absence of right ankle |
| Z89442 | Acquired absence of left ankle |
| Z89449 | Acquired absence of unspecified ankle |
| Z89511 | Acquired absence of right leg below knee |
| Z89512 | Acquired absence of left leg below knee |
| Z89519 | Acquired absence of unspecified leg below knee |
| Z89611 | Acquired absence of right leg above knee |
| Z89612 | Acquired absence of left leg above knee |
| Z89619 | Acquired absence of unspecified leg above knee |
| Z9713 | Presence of artificial right leg (complete) (partial) |
| Z9714 | Presence of artificial left leg (complete) (partial) |
| Z9716 | Presence of artificial legs, bilateral (complete) (partial) |
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 |
|---|---|
| 189 | 41 |
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 409?
44 ICD-10-CM codes map to HCC 409 in the CMS PY2027 initial mapping, for example G546 Phantom limb syndrome with pain; G547 Phantom limb syndrome without pain; T8730 Neuroma of amputation stump, unspecified extremity; T8731 Neuroma of amputation stump, right upper extremity. 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 409 add to a risk score?
The V28 relative factor for HCC 409 is 0.598 for a community, non-dual, aged beneficiary, 0.799 for full-benefit dual aged, 0.562 for non-dual disabled and 0.284 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 409 count together with related categories?
No. Within a hierarchy only the most severe category is paid. HCC 409 is dropped when HCC 263 (Atherosclerosis of Arteries of the Extremities with Ulceration or Gangrene) or HCC 405 (Traumatic Amputations and Complications) is also present.
What has to be documented for HCC 409 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.