2027 ICD-10-CM Diagnosis Code I82.4Y1Acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity
ICD-10-CM Codes›I00–I99›I80-I89›I82
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 267
- Not Chronic
I82.4Y1 is a billable ICD-10-CM diagnosis code for acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 299 through 301. 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 201 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute phlebitis; thrombophlebitis and thromboembolism.
For Medicare Advantage risk adjustment, I82.4Y1 maps to CMS-HCC Category 267 (Deep Vein Thrombosis and Pulmonary Embolism) under the V28 model, adding a risk factor of about 0.294 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
I82.4Y1 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.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to I82.4Y1: its own notes plus those printed at I82 and Chapter 9. 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.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- transient cerebral ischemic attacks and related syndromes (G45.-)
Code First
The underlying condition named in the note is sequenced before this code.
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name I82.4Y1, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming I82.4Y1: they are not reported together with it, unless the two conditions are unrelated.
- I80 Phlebitis and thrombophlebitisvenous embolism and thrombosis of lower extremities (I82.4-, I82.5-, I82.81-) names I82.4-, which includes this code
- I82.40 Acute embolism and thrombosis of unspecified deep veins of lower extremityacute embolism and thrombosis of unspecified deep veins of proximal lower extremity (I82.4Y-) names I82.4Y-, which includes this code
Use Additional Code 2
These codes say to use an additional code from the note, and I82.4Y1 is one of the codes named.
- O22.3 Deep phlebothrombosis in pregnancycode to identify the deep vein thrombosis (I82.4-, I82.5-, I82.62-, I82.72-) names I82.4-, which includes this code
- O87.1 Deep phlebothrombosis in the puerperiumcode to identify the deep vein thrombosis (I82.4-, I82.5-, I82.62-, I82.72-) names I82.4-, which includes this code
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Deep Vein Thrombosis
Deep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or thigh. If the vein swells, the condition is called thrombophlebitis. A deep vein thrombosis can break loose and cause a serious problem in the lung, called a pulmonary embolism.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I82.4Y1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I82.4Y1Overview
Is I82.4Y1 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does I82.4Y1 group to?
When acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity is the principal diagnosis on an inpatient stay, it groups to MS-DRG 301, 300, 299, with relative weights from 0.7132 to 1.5840 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I82.4Y1 a CC or MCC?
CMS lists I82.4Y1 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 201 closely related codes in its exclusion list.
What is coded first with I82.4Y1?
The Code First note at I82, which applies to I82.4Y1, reads: venous embolism and thrombosis complicating: abortion, ectopic or molar pregnancy (O00-O07, O08.7); pregnancy, childbirth and the puerperium (O22.-, O87.-). When one of these applies, it is sequenced before I82.4Y1.
What is the ICD-9 equivalent of I82.4Y1?
Under the General Equivalence Mappings, acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity converts to ICD-9-CM 453.41 (ac DVT/emb prox low ext). The mapping is approximate, so confirm the match fits the documentation.
What HCC is I82.4Y1?
I82.4Y1 (acute embolism and thrombosis of unspecified deep veins of right proximal lower extremity) maps to CMS-HCC Category 267 (Deep Vein Thrombosis and Pulmonary Embolism), commonly written as HCC 267, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 108 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 215.
Does I82.4Y1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, I82.4Y1 adds a risk adjustment factor of about 0.294 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.245 to 0.568 depending on the payment segment). HCC 267 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 267 category page.
