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_HCC405 | 0.598 |
| Community, non-dual, disabled | CND_HCC405 | 0.577 |
| Community, full-benefit dual, aged | CFA_HCC405 | 0.799 |
| Community, full-benefit dual, disabled | CFD_HCC405 | 0.844 |
| Community, partial-benefit dual, aged | CPA_HCC405 | 0.639 |
| Community, partial-benefit dual, disabled | CPD_HCC405 | 0.698 |
| Long-term institutional | INS_HCC405 | 0.284 |
Hierarchy
Hierarchical condition categories pay only the most severe manifestation of a disease. HCC 405 is the most severe category in its hierarchy. When HCC 405 is present it drops HCC 409 (Amputation Status, Lower Limb/Amputation Complications), 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 405
108 codes map to this category in the PY2027 initial mapping, concentrated in the S48 (18), S58 (18), S78 (18), S88 (18), S98 (18), S68 (12) 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 |
|---|---|
| S48011A | Complete traumatic amputation at right shoulder joint, initial encounter |
| S48012A | Complete traumatic amputation at left shoulder joint, initial encounter |
| S48019A | Complete traumatic amputation at unspecified shoulder joint, initial encounter |
| S48021A | Partial traumatic amputation at right shoulder joint, initial encounter |
| S48022A | Partial traumatic amputation at left shoulder joint, initial encounter |
| S48029A | Partial traumatic amputation at unspecified shoulder joint, initial encounter |
| S48111A | Complete traumatic amputation at level between right shoulder and elbow, initial encounter |
| S48112A | Complete traumatic amputation at level between left shoulder and elbow, initial encounter |
| S48119A | Complete traumatic amputation at level between unspecified shoulder and elbow, initial encounter |
| S48121A | Partial traumatic amputation at level between right shoulder and elbow, initial encounter |
| S48122A | Partial traumatic amputation at level between left shoulder and elbow, initial encounter |
| S48129A | Partial traumatic amputation at level between unspecified shoulder and elbow, initial encounter |
| S48911A | Complete traumatic amputation of right shoulder and upper arm, level unspecified, initial encounter |
| S48912A | Complete traumatic amputation of left shoulder and upper arm, level unspecified, initial encounter |
| S48919A | Complete traumatic amputation of unspecified shoulder and upper arm, level unspecified, initial encounter |
| S48921A | Partial traumatic amputation of right shoulder and upper arm, level unspecified, initial encounter |
| S48922A | Partial traumatic amputation of left shoulder and upper arm, level unspecified, initial encounter |
| S48929A | Partial traumatic amputation of unspecified shoulder and upper arm, level unspecified, initial encounter |
| S58011A | Complete traumatic amputation at elbow level, right arm, initial encounter |
| S58012A | Complete traumatic amputation at elbow level, left arm, initial encounter |
| S58019A | Complete traumatic amputation at elbow level, unspecified arm, initial encounter |
| S58021A | Partial traumatic amputation at elbow level, right arm, initial encounter |
| S58022A | Partial traumatic amputation at elbow level, left arm, initial encounter |
| S58029A | Partial traumatic amputation at elbow level, unspecified arm, initial encounter |
| S58111A | Complete traumatic amputation at level between elbow and wrist, right arm, initial encounter |
| S58112A | Complete traumatic amputation at level between elbow and wrist, left arm, initial encounter |
| S58119A | Complete traumatic amputation at level between elbow and wrist, unspecified arm, initial encounter |
| S58121A | Partial traumatic amputation at level between elbow and wrist, right arm, initial encounter |
| S58122A | Partial traumatic amputation at level between elbow and wrist, left arm, initial encounter |
| S58129A | Partial traumatic amputation at level between elbow and wrist, unspecified arm, initial encounter |
| S58911A | Complete traumatic amputation of right forearm, level unspecified, initial encounter |
| S58912A | Complete traumatic amputation of left forearm, level unspecified, initial encounter |
| S58919A | Complete traumatic amputation of unspecified forearm, level unspecified, initial encounter |
| S58921A | Partial traumatic amputation of right forearm, level unspecified, initial encounter |
| S58922A | Partial traumatic amputation of left forearm, level unspecified, initial encounter |
| S58929A | Partial traumatic amputation of unspecified forearm, level unspecified, initial encounter |
| S68411A | Complete traumatic amputation of right hand at wrist level, initial encounter |
| S68412A | Complete traumatic amputation of left hand at wrist level, initial encounter |
| S68419A | Complete traumatic amputation of unspecified hand at wrist level, initial encounter |
| S68421A | Partial traumatic amputation of right hand at wrist level, initial encounter |
| S68422A | Partial traumatic amputation of left hand at wrist level, initial encounter |
| S68429A | Partial traumatic amputation of unspecified hand at wrist level, initial encounter |
| S68711A | Complete traumatic transmetacarpal amputation of right hand, initial encounter |
| S68712A | Complete traumatic transmetacarpal amputation of left hand, initial encounter |
| S68719A | Complete traumatic transmetacarpal amputation of unspecified hand, initial encounter |
| S68721A | Partial traumatic transmetacarpal amputation of right hand, initial encounter |
| S68722A | Partial traumatic transmetacarpal amputation of left hand, initial encounter |
| S68729A | Partial traumatic transmetacarpal amputation of unspecified hand, initial encounter |
| S78011A | Complete traumatic amputation at right hip joint, initial encounter |
| S78012A | Complete traumatic amputation at left hip joint, initial encounter |
| S78019A | Complete traumatic amputation at unspecified hip joint, initial encounter |
| S78021A | Partial traumatic amputation at right hip joint, initial encounter |
| S78022A | Partial traumatic amputation at left hip joint, initial encounter |
| S78029A | Partial traumatic amputation at unspecified hip joint, initial encounter |
| S78111A | Complete traumatic amputation at level between right hip and knee, initial encounter |
| S78112A | Complete traumatic amputation at level between left hip and knee, initial encounter |
| S78119A | Complete traumatic amputation at level between unspecified hip and knee, initial encounter |
| S78121A | Partial traumatic amputation at level between right hip and knee, initial encounter |
| S78122A | Partial traumatic amputation at level between left hip and knee, initial encounter |
| S78129A | Partial traumatic amputation at level between unspecified hip and knee, initial encounter |
| S78911A | Complete traumatic amputation of right hip and thigh, level unspecified, initial encounter |
| S78912A | Complete traumatic amputation of left hip and thigh, level unspecified, initial encounter |
| S78919A | Complete traumatic amputation of unspecified hip and thigh, level unspecified, initial encounter |
| S78921A | Partial traumatic amputation of right hip and thigh, level unspecified, initial encounter |
| S78922A | Partial traumatic amputation of left hip and thigh, level unspecified, initial encounter |
| S78929A | Partial traumatic amputation of unspecified hip and thigh, level unspecified, initial encounter |
| S88011A | Complete traumatic amputation at knee level, right lower leg, initial encounter |
| S88012A | Complete traumatic amputation at knee level, left lower leg, initial encounter |
| S88019A | Complete traumatic amputation at knee level, unspecified lower leg, initial encounter |
| S88021A | Partial traumatic amputation at knee level, right lower leg, initial encounter |
| S88022A | Partial traumatic amputation at knee level, left lower leg, initial encounter |
| S88029A | Partial traumatic amputation at knee level, unspecified lower leg, initial encounter |
| S88111A | Complete traumatic amputation at level between knee and ankle, right lower leg, initial encounter |
| S88112A | Complete traumatic amputation at level between knee and ankle, left lower leg, initial encounter |
| S88119A | Complete traumatic amputation at level between knee and ankle, unspecified lower leg, initial encounter |
| S88121A | Partial traumatic amputation at level between knee and ankle, right lower leg, initial encounter |
| S88122A | Partial traumatic amputation at level between knee and ankle, left lower leg, initial encounter |
| S88129A | Partial traumatic amputation at level between knee and ankle, unspecified lower leg, initial encounter |
| S88911A | Complete traumatic amputation of right lower leg, level unspecified, initial encounter |
| S88912A | Complete traumatic amputation of left lower leg, level unspecified, initial encounter |
| S88919A | Complete traumatic amputation of unspecified lower leg, level unspecified, initial encounter |
| S88921A | Partial traumatic amputation of right lower leg, level unspecified, initial encounter |
| S88922A | Partial traumatic amputation of left lower leg, level unspecified, initial encounter |
| S88929A | Partial traumatic amputation of unspecified lower leg, level unspecified, initial encounter |
| S98011A | Complete traumatic amputation of right foot at ankle level, initial encounter |
| S98012A | Complete traumatic amputation of left foot at ankle level, initial encounter |
| S98019A | Complete traumatic amputation of unspecified foot at ankle level, initial encounter |
| S98021A | Partial traumatic amputation of right foot at ankle level, initial encounter |
| S98022A | Partial traumatic amputation of left foot at ankle level, initial encounter |
| S98029A | Partial traumatic amputation of unspecified foot at ankle level, initial encounter |
| S98311A | Complete traumatic amputation of right midfoot, initial encounter |
| S98312A | Complete traumatic amputation of left midfoot, initial encounter |
| S98319A | Complete traumatic amputation of unspecified midfoot, initial encounter |
| S98321A | Partial traumatic amputation of right midfoot, initial encounter |
| S98322A | Partial traumatic amputation of left midfoot, initial encounter |
| S98329A | Partial traumatic amputation of unspecified midfoot, initial encounter |
| S98911A | Complete traumatic amputation of right foot, level unspecified, initial encounter |
| S98912A | Complete traumatic amputation of left foot, level unspecified, initial encounter |
| S98919A | Complete traumatic amputation of unspecified foot, level unspecified, initial encounter |
| S98921A | Partial traumatic amputation of right foot, level unspecified, initial encounter |
| S98922A | Partial traumatic amputation of left foot, level unspecified, initial encounter |
| S98929A | Partial traumatic amputation of unspecified foot, level unspecified, initial encounter |
| T870X1 | Complications of reattached (part of) right upper extremity |
| T870X2 | Complications of reattached (part of) left upper extremity |
| T870X9 | Complications of reattached (part of) unspecified upper extremity |
| T871X1 | Complications of reattached (part of) right lower extremity |
| T871X2 | Complications of reattached (part of) left lower extremity |
| T871X9 | Complications of reattached (part of) unspecified lower extremity |
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 |
|---|---|
| 173 | 108 |
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 405?
108 ICD-10-CM codes map to HCC 405 in the CMS PY2027 initial mapping, for example S48011A Complete traumatic amputation at right shoulder joint, initial encounter; S48012A Complete traumatic amputation at left shoulder joint, initial encounter; S48019A Complete traumatic amputation at unspecified shoulder joint, initial encounter; S48021A Partial traumatic amputation at right shoulder joint, initial encounter. 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 405 add to a risk score?
The V28 relative factor for HCC 405 is 0.598 for a community, non-dual, aged beneficiary, 0.799 for full-benefit dual aged, 0.577 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 405 count together with related categories?
No. Within a hierarchy only the most severe category is paid. HCC 405 is the most severe category in its hierarchy, and it drops HCC 409 when it is present.
What has to be documented for HCC 405 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.