🧬 ICD-10 CM I82.C12 — Acute Embolism and Thrombosis of Left Internal Jugular Vein
Billable Code Confirmed
ICD-10 CM I82.C12 is a fully specified, billable 6-character code: the first three characters (I82) identify the category, the fourth character (.C) specifies the internal jugular vein, the fifth character (1) designates acute presentation, and the sixth character (2) specifies laterality as left. With vein, acuity, and laterality all captured, no further specificity is required.
Non-Billable Parent Codes
I82 (venous embolism and thrombosis, unspecified) — lacks vein site, acuity, and laterality and cannot be billed. I82.C (embolism and thrombosis of internal jugular vein) — identifies the vein but not acuity or laterality. I82.C1 (acute embolism and thrombosis of internal jugular vein) — identifies acuity but omits laterality, so a sixth character is required before it is billable.
Clinical Context
Selection of I82.C12 over its siblings depends on documentation of laterality (left versus right versus bilateral) and confirmation that the thrombus is acute rather than chronic/organized; internal jugular vein thrombosis is increasingly recognized in the setting of indwelling central venous catheters, pacemaker/ICD leads, and head-and-neck malignancy, so the underlying etiology should also be captured when documented.
Code Classification
ICD-10 CM I82.C12 is a diagnosis code (ICD-10-CM), not a procedure code, and represents an acute vascular/thrombotic condition rather than a chronic status code.
🔍 Code Description
ICD-10 CM I82.C12 describes an acute thrombus occupying the left internal jugular vein, the major deep venous conduit draining blood from the brain, face, and neck into the left brachiocephalic vein. This code is distinguished from its right-sided sibling I82.C11 by laterality alone, and from the subclavian-vein family such as I82.B12 (acute left subclavian vein thrombosis) by the specific vessel affected — an important distinction in patients with central venous catheters, since catheter tip position determines which named vein is thrombosed. Internal jugular vein thrombosis is most frequently encountered in the otolaryngology and head-and-neck oncology population secondary to indwelling central lines, pacemaker or defibrillator leads, IV drug use, deep neck space infection (historically termed Lemierre syndrome when septic), or direct tumor compression/invasion.
Clinically, left IJ vein thrombosis presents with unilateral neck swelling, tenderness along the sternocleidomastoid muscle, and occasionally facial or periorbital edema on the affected side; a substantial number of cases are identified incidentally on CT or ultrasound imaging obtained for another indication, particularly in oncology patients undergoing surveillance imaging. Unlike lower-extremity DVT codes such as I82.401, I82.C12 sits within the upper-body/central venous thrombosis family alongside I82.A12 (axillary vein, left) and I82.B12 (subclavian vein, left), and precise vein-level documentation is essential since these codes are not interchangeable.
🌳 Code Tree / Hierarchy
I82 Other venous embolism and thrombosis ❌ Non-billable
│
├── I82.B Embolism and thrombosis of subclavian vein ❌ Non-billable
│ └── I82.B1 Acute embolism and thrombosis of subclavian vein ❌ Non-billable (category)
│ └── I82.B12 Acute embolism and thrombosis of left subclavian vein ✅ Billable
│
├── I82.C Embolism and thrombosis of internal jugular vein ❌ Non-billable
│ │
│ ├── I82.C1 Acute embolism and thrombosis of internal jugular vein ❌ Non-billable (category)
│ │ │
│ │ ├── I82.C11 Acute embolism and thrombosis of right internal jugular vein ✅ Billable
│ │ ├── I82.C12 Acute embolism and thrombosis of left internal jugular vein ◀ THIS CODE ✅ Billable
│ │ ├── I82.C13 Acute embolism and thrombosis of internal jugular vein, bilateral ✅ Billable
│ │ └── I82.C19 Acute embolism and thrombosis of unspecified internal jugular vein ✅ Billable
│ │
│ └── I82.C2 Chronic embolism and thrombosis of internal jugular vein ❌ Non-billable (category)
│ └── I82.C22 Chronic embolism and thrombosis of left internal jugular vein ✅ Billable
│
└── I82.8 Embolism and thrombosis of other specified veins ❌ Non-billableSpecificity Distinguishes Central Venous Thrombosis Sites
Payers and clinical registries increasingly track catheter-associated thrombosis by exact vessel — internal jugular, subclavian, or axillary — since this affects catheter management decisions (remove vs. retain the line); selecting I82.C1x accurately rather than a generic upper-extremity or unspecified vein code preserves that clinical detail in the record.
Tip
Confirm from the imaging report (duplex ultrasound or CT venogram) exactly which vessel is thrombosed — internal jugular versus external jugular versus subclavian versus brachiocephalic — since these are coded to entirely different fifth-character categories under I82.
✅ Includes
- Acute deep vein thrombosis of the left internal jugular vein.
- Newly diagnosed embolism or thrombus in this specific vein and laterality, without reference to prior chronic thrombotic disease.
- Catheter-associated left internal jugular vein thrombosis, when the thrombus itself is the focus of the code (report the mechanical/infectious complication of the device separately per ICD-10-CM device-complication coding guidelines when applicable).
❌ Excludes
Excludes 1
No Excludes1 note applies directly at the I82.C12 code level, since acuity and laterality are already fully specified once the internal jugular vein is identified as the affected site.
Danger
A common Excludes1-adjacent error is coding both an acute (I82.C12) and a chronic (I82.C22) internal jugular vein thrombosis code for the same vessel and encounter — acute and chronic embolism/thrombosis codes are mutually exclusive for the same vein at a given point in time, so the provider’s documentation of acuity should govern code selection, not both codes simultaneously.
Excludes 2
ICD-10 CM I26.99 (or other applicable I26.- code) — Acute pulmonary embolism; because internal jugular vein thrombosis can rarely embolize, both a central venous thrombosis code and a pulmonary embolism code may be reported together when both conditions are separately documented. I63.6/I67.6 — Cerebral venous thrombosis is anatomically distinct (intracranial rather than extracranial neck vein) and is coded separately when present. I81 — Portal vein thrombosis reflects a different venous territory entirely and may be coded concurrently if separately documented.
📋 Clinical Overview
Central Venous Thrombosis by Vessel Site
Distinguishing internal jugular vein thrombosis from subclavian and axillary vein thrombosis is the key clinical distinction driving code selection within the upper-body venous thrombosis family, since catheter position and management decisions depend on the exact vessel involved.
| Feature | I82.C12 | Related I82.B12 | Related I82.A12 |
|---|---|---|---|
| Anatomic location | Left internal jugular vein, draining the head and neck. | Left subclavian vein, at the thoracic outlet. | Left axillary vein, in the upper arm/shoulder region. |
| Common etiology | Central venous catheters placed via the IJ approach, deep neck infection, head-and-neck malignancy, pacemaker/ICD leads. | Subclavian catheter placement, thoracic outlet syndrome, effort thrombosis (Paget-Schroetter syndrome context). | PICC lines, axillary vein catheterization, effort-related thrombosis. |
| Typical presentation | Unilateral neck swelling, tenderness along the sternocleidomastoid, occasional facial edema. | Ipsilateral arm and shoulder swelling, chest wall venous distension. | Arm swelling, typically less dramatic than subclavian-level thrombosis. |
Important
A CDI query is warranted whenever documentation states only “neck vein thrombosis” or “IJ clot” without specifying laterality, since laterality is required for full sixth-character code selection and cannot be assumed from catheter side alone if not explicitly documented.
Manifestations & Symptom Burden
- Unilateral neck swelling and tenderness along the course of the sternocleidomastoid muscle.
- Erythema or warmth over the affected side of the neck.
- Ipsilateral facial or periorbital edema in more extensive cases.
- Low-grade fever, particularly when the thrombosis is infection-associated (septic thrombophlebitis).
- Asymptomatic presentation, frequently identified incidentally on CT or ultrasound imaging performed for another indication (common in oncology surveillance).
Tip
Document whether the thrombosis is catheter-associated, infection-associated, or malignancy-associated, since this etiology materially affects both anticoagulation decisions (e.g., whether to remove an indwelling line) and completeness of the coded record.
💰 HCC Risk Adjustment
| Model | HCC Category | RAF Weight | Notes |
|---|---|---|---|
| CMS-HCC V28 (PY2026) | N/A — not currently a payment HCC | N/A | Acute central venous thrombosis codes are not among the 115 current payment HCC categories — flag to verify against current CMS-HCC V28 model software rather than relying solely on this note. |
ICD-10 CM I82.C12 does not independently generate risk-adjustment value under the fully phased-in CMS-HCC V28 model for Payment Year 2026. If the thrombosis is secondary to an HCC-eligible chronic condition — active malignancy, a hypercoagulable disorder, or another chronic risk-bearing diagnosis — that underlying condition should be identified, documented with MEAT criteria, and coded separately, since it (not I82.C12 itself) carries RAF value.
🏥 MS-DRG Assignment
| DRG | Title | CC/MCC Tier |
|---|---|---|
| 299 | Peripheral Vascular Disorders | With MCC |
| 300 | Peripheral Vascular Disorders | With CC |
| 301 | Peripheral Vascular Disorders | Without CC/MCC |
When reported as principal diagnosis for an inpatient stay focused on diagnosis and anticoagulation management of left internal jugular vein thrombosis, I82.C12 typically groups to MDC 05 Peripheral Vascular Disorders (DRG 299-301); DRG weight is driven largely by secondary diagnosis capture (central line complication, active malignancy, concurrent infection, bleeding complications from anticoagulation) rather than by the thrombosis code alone — flag exact DRG relative weights for direct verification against the current IPPS Final Rule. NCD/LCD note: no dedicated National Coverage Determination specific to internal jugular vein thrombosis or I82.C12 was identified in the current Medicare Coverage Database search.¹ CMS NCD 190.11 (Home Prothrombin Time/INR Monitoring for Anticoagulation Management) applies broadly to venous thromboembolism managed with chronic oral warfarin therapy and may extend to central venous thrombosis when the patient meets the same 3-month anticoagulation, education, and self-testing-frequency criteria, though the NCD’s published language is framed primarily around DVT/PE rather than central/jugular sites — verify applicability with your MAC.² Local MAC billing-and-coding articles covering peripheral/central venous ultrasound (e.g., Non-Invasive Peripheral Venous Studies articles) commonly list I82.C1x codes among the covered diagnoses supporting medical necessity for duplex ultrasound CPT codes 93970/93971 — verify current diagnosis-code coverage lists against your specific MAC’s active article.³
🔗 Related ICD-10-CM Codes
Same Vein Group — Laterality/Acuity Variants
- I82.C11 — Acute embolism and thrombosis of right internal jugular vein
- I82.C13 — Acute embolism and thrombosis of internal jugular vein, bilateral
- I82.C19 — Acute embolism and thrombosis of unspecified internal jugular vein
- I82.C22 — Chronic embolism and thrombosis of left internal jugular vein
Adjacent Central/Upper-Body Venous Thrombosis Sites
- I82.B12 — Acute embolism and thrombosis of left subclavian vein
- I82.A12 — Acute embolism and thrombosis of left axillary vein
- I82.290 — Acute embolism and thrombosis of other thoracic veins (includes brachiocephalic/innominate vein)
- I26.99 — Other pulmonary embolism without acute cor pulmonale (if concurrent PE is documented)
🛠️ Commonly Associated CPT Codes
- 93970 — Duplex scan of extremity veins including responses to compression and other maneuvers; complete bilateral study; some MACs’ peripheral/central venous ultrasound articles list I82.C1x among covered diagnoses when a comprehensive bilateral neck/upper-body venous evaluation is performed.
- 93971 — Duplex scan of extremity veins; unilateral or limited study; the more commonly applicable code when only the left internal jugular vein is evaluated.
- 36556 — Insertion of non-tunneled centrally inserted central venous catheter; relevant when catheter removal/replacement is planned due to catheter-associated thrombosis.
- 36581 — Replacement, complete, of a non-tunneled centrally inserted central venous catheter; relevant if the line is exchanged rather than simply removed.
- 37187 — Percutaneous transluminal mechanical thrombectomy, vein(s), including intraprocedural pharmacological thrombolytic injections; used when catheter-directed mechanical clot removal is performed for extensive or symptomatic thrombus.
🏷️ Modifier Reference
| Modifier | Name | When to Apply |
|---|---|---|
| -LT | Left Side | Apply to any associated procedure code (e.g., 93971) to specify that the left-sided internal jugular vein was the one studied or treated, consistent with I82.C12’s laterality. |
| -RT | Right Side | Not applicable to this specific left-sided diagnosis, but relevant if a bilateral duplex study is billed separately for each side. |
| -59 | Distinct Service | Apply when a separately identifiable duplex ultrasound or procedure is performed on a different, unrelated anatomic site on the same date. |
| -76 | Repeat Procedure, Same Physician | Apply when a repeat duplex ultrasound is performed by the same physician to reassess clot progression or resolution on a later date. |
NCCI Bundling Considerations
Diagnostic duplex ultrasound (93971) is generally not bundled with a subsequent catheter removal or exchange procedure (36581) performed on the same date when both a distinct diagnostic evaluation and a separately identifiable procedural decision are clearly documented; append modifier -59 only when medical necessity and distinct service are clearly supported in the record.
🔬 ICD-10-PCS Crosswalk
ICD-10 CM I82.C12 is a diagnosis code and does not itself convert to a procedure code; the following PCS codes represent common inpatient procedures performed to treat the condition it describes.
05CN3ZZ— Extirpation, left internal jugular vein, percutaneous approach; the most likely PCS code when percutaneous mechanical or pharmacomechanical thrombectomy is performed to remove the thrombus from the left internal jugular vein — flag to verify against your encoder for the exact body-part value.3E0P3GC— Introduction of thrombolytic agent into central vein, percutaneous approach; applies when catheter-directed thrombolytic therapy is administered for extensive central venous thrombosis.0WPD0YZor similar device-removal code — Removal of a device (indwelling central venous catheter) from the left internal jugular vein or associated vascular access site, if the catheter is removed as part of treating the thrombosis — flag exact body-part and device-value characters for direct verification. Confirm exact body-part and approach characters against your facility’s encoder, since ICD-10-PCS defines central venous structures at a level of granularity that requires direct chart verification.
💊 Coding Scenarios and Examples
Example 1
Clinical Scenario:
A 62-year-old male with an indwelling left internal jugular tunneled dialysis catheter presents with left neck swelling and tenderness. Duplex ultrasound confirms acute thrombus in the left internal jugular vein without extension. Anticoagulation is initiated and the catheter is retained after multidisciplinary discussion.
| Field | Code | Rationale |
|---|---|---|
| CPT | 93971--LT | Unilateral limited duplex scan of the left internal jugular vein confirming the diagnosis. |
| PDx | I82.C12 | Acute embolism and thrombosis of the left internal jugular vein is the confirmed, fully specified principal diagnosis. |
Tip
Sequencing explanation: I82.C12 is sequenced as principal diagnosis since it is the condition prompting the encounter; document the dialysis catheter’s continued presence and the rationale for retaining rather than removing it, since this affects the completeness of the record and any associated device-complication coding. CDI note: if the catheter is documented as the causative mechanical factor, confirm whether a device-complication code is also warranted per ICD-10-CM Chapter 19 guidelines.
Example 2
Clinical Scenario:
A 55-year-old female with active head and neck squamous cell carcinoma undergoing chemoradiation develops left neck swelling; CT neck with contrast confirms acute left internal jugular vein thrombosis, felt secondary to tumor compression and hypercoagulability of malignancy. She is admitted for anticoagulation initiation.
| Field | Code | Rationale |
|---|---|---|
| CPT | 93971--LT | Diagnostic duplex/imaging confirmation of the left-sided internal jugular vein thrombus (if duplex ultrasound is used to confirm CT findings). |
| CPT 2 | 36000 | Peripheral venous access established for anticoagulant administration and monitoring. |
| PDx | I82.C12 | Principal diagnosis reflecting the confirmed acute left internal jugular vein thrombosis prompting admission. |
Tip
Sequencing explanation: code the active head and neck malignancy as an additional diagnosis since it is being actively treated and is clinically significant to the hypercoagulable state, even though the DVT code itself carries no HCC weight. CDI note: confirm whether the physician documents the malignancy as the causative etiology of the thrombosis, since this strengthens medical necessity documentation for anticoagulation in a cancer patient.
Example 3
Clinical Scenario:
A 40-year-old male returns one week after initial diagnosis of acute left internal jugular vein thrombosis for a follow-up duplex ultrasound, performed by the same physician, to confirm clot stability prior to continuing outpatient anticoagulation.
| Field | Code | Rationale |
|---|---|---|
| CPT | 93971--LT--76 | Modifier -76 identifies this as a repeat duplex study by the same physician performed to reassess the previously diagnosed thrombus. |
| PDx | I82.C12 | The condition being monitored remains the acute left internal jugular vein thrombosis. |
Tip
Sequencing explanation: continue reporting the acute code as long as the thrombus remains active/unresolved; if the follow-up study demonstrates full resolution, transition to an appropriate history-of-thrombosis status code at the next encounter rather than continuing to report the acute code indefinitely. CDI note: if imaging instead shows the clot has organized into a chronic, non-resolving thrombus rather than resolving, query the provider regarding transition to the chronic code I82.C22.
⚠️ Coding Pitfalls and Tips
- Pitfall 1: Defaulting to a generic upper-extremity or unspecified vein code when the imaging report clearly documents the internal jugular vein specifically; Tips: Always read the full imaging report rather than the referring diagnosis alone, since the exact named vessel determines the correct fifth-character category (I82.A axillary, I82.B subclavian, I82.C internal jugular).
- Pitfall 2: Omitting laterality and defaulting to the unspecified sixth character I82.C19 when the chart clearly documents “left” or “right”; Tips: Query the provider if laterality is ambiguous rather than defaulting to unspecified, since laterality specificity is required for full code accuracy.
- Pitfall 3: Failing to also code the indwelling central venous catheter complication when the device is documented as the causative mechanism of the thrombosis; Tips: Review Chapter 19 device-complication coding guidelines and query the provider regarding causal linkage between the catheter and the thrombosis when documentation is ambiguous.
- Pitfall 4: Assuming I82.C12 carries HCC risk-adjustment value under CMS-HCC V28, leading to missed opportunities to instead capture the true HCC-relevant underlying condition (e.g., active malignancy); Tips: Review the chart for an HCC-eligible etiology and code it separately with full MEAT documentation.
- Pitfall 5: Reporting both the acute (I82.C12) and chronic (I82.C22) internal jugular vein thrombosis codes for the same vessel at the same encounter; Tips: Confirm the provider’s stated acuity in the current encounter’s documentation and select only the code matching that acuity.
- Pitfall 6: Confusing internal jugular vein thrombosis with cerebral venous sinus thrombosis (an intracranial condition coded under I63.6 or I67.6) due to anatomic proximity in the neck/head region; Tips: Confirm from the imaging report whether the thrombosed vessel is extracranial (internal jugular vein, coded I82.C1x) versus intracranial (cerebral venous sinus, coded I63.6/I67.6), since these represent entirely different code families with different clinical implications.
📚 Sources
1. Centers for Medicare & Medicaid Services. *Medicare Coverage Database (MCD) — NCD/LCD Search.* CMS.gov; 2026. https://www.cms.gov/medicare-coverage-database 2. Centers for Medicare & Medicaid Services. *National Coverage Determination (NCD) 190.11: Home Prothrombin Time/International Normalized Ratio (PT/INR) Monitoring for Anticoagulation Management.* CMS Pub. 100-03; 2026. https://www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?ncdid=269 3. Centers for Medicare & Medicaid Services (Medicare Administrative Contractor). *Billing and Coding: Non-Invasive Peripheral Venous Studies / Peripheral Venous Ultrasound, Local Coverage Article.* CMS Medicare Coverage Database; 2026. https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=52993 4. Centers for Medicare and Medicaid Services and the National Center for Health Statistics. *ICD-10-CM 2026, Code I82.C12.* NCHS; 2026. https://www.icd10data.com/ICD10CM/Codes/I00-I99/I80-I89/I82-/I82.C12 5. HCC Buddy. *CMS-HCC V28 Guide 2026: 115 HCCs, Weights.* 2026. https://hccbuddy.com/hcc-v28Sources listed above correspond to superscript citations throughout this note. Verify all Medicare payment figures against your current CMS PFS Lookup tool and applicable MAC LCD prior to claim submission. Please use the latest AAPC/AHIMA Coding Books to verify each code within this note.