2027 ICD-10-CM Diagnosis Code S98.321APartial traumatic amputation of right midfoot, initial encounter
ICD-10-CM Codes›S00–T88›S90-S99›S98
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 405
- 7th Character A — Initial Encounter
- Chronic Condition
S98.321A is a billable ICD-10-CM diagnosis code for partial traumatic amputation of right midfoot, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 913 through 914, 963 through 965. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 229 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Amputation of a limb, initial encounter.
For Medicare Advantage risk adjustment, S98.321A maps to CMS-HCC Category 405 (Traumatic Amputations and Complications) under the V28 model, adding a risk factor of about 0.598 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
S98.321A maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Coding GuidelinesGuidance
The appropriate 7th character is to be added to each code from block Traumatic amputation of ankle and foot (S98). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to S98.321A: its own notes plus those printed at S98, block S90-S99, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category S98
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name S98.321A, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming S98.321A: they are not reported together with it, unless the two conditions are unrelated.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Limb Loss
People can lose all or part of an arm or leg for many reasons. Common ones include:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert S98.321A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About S98.321AOverview
What is the ICD-10 code for partial traumatic amputation of right midfoot, initial encounter?
The ICD-10-CM code for partial traumatic amputation of right midfoot, initial encounter is S98.321A (sometimes written as S98321A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is S98.321A (Partial traumatic amputation of right midfoot) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report partial traumatic amputation of right midfoot, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in S98.321A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for partial traumatic amputation of right midfoot, such as an emergency visit or first evaluation.
What MS-DRG does S98.321A group to?
When partial traumatic amputation of right midfoot, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 964, 965, 914, 913, 963, with relative weights from 0.9281 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.
Is S98.321A a CC or MCC?
CMS lists S98.321A as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 229 closely related codes in its exclusion list.
What HCC is S98.321A?
S98.321A (partial traumatic amputation of right midfoot, initial encounter) maps to CMS-HCC Category 405 (Traumatic Amputations and Complications), commonly written as HCC 405, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 173 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does S98.321A risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, S98.321A adds a risk adjustment factor of about 0.598 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.284 to 0.844 depending on the payment segment). HCC 405 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 405 category page.
