ICD-10 Code S35.311D: Laceration of portal vein, subsequent encounter

Key Takeaways

ICD-10 Code S35.311D describes a laceration of the portal vein coded at a subsequent encounter – the patient is receiving active care for an injury that has already been treated.

S35.311D is a billable/specific ICD-10-CM code effective October 1, 2025 (FY2026); the parent code S35.311 without a 7th character is non-billable.

Three billable child codes exist: S35.311A (initial encounter), S35.311D (subsequent encounter), and S35.311S (sequela) – choosing incorrectly risks claim denial.

Pabau’s claims management software helps coders document subsequent encounter visits accurately and submit clean claims with the correct 7th character extension.

ICD-10 Code S35.311D: Definition and billable status

Most claim denials involving portal vein trauma come down to one character. ICD-10 Code S35.311D – Laceration of portal vein, subsequent encounter – is the billable code coders reach for when a patient with a documented portal vein laceration returns for active follow-up care. Getting the 7th character wrong (using “A” on a subsequent visit, for example) triggers a denial that takes weeks to resolve. Accurate claims management begins with understanding exactly what this code means and when to use it.

S35.311D is a billable/specific ICD-10-CM code confirmed in the FY2026 code set, effective for discharges and encounters on or after October 1, 2025. Per the CMS ICD-10 codes page, this code falls under chapter S00-T88 (Injury, poisoning and certain other consequences of external causes). Its parent, S35.311, carries no billable status on its own – a 7th character extension is always required before submitting a claim.

S35.311D code details at a glance

The table below summarises the key reference fields coders need when working with ICD-10 Code S35.311D in documentation or billing workflows.

Coders working in integrated EHR environments should confirm the full 8-character string “S35.311D” appears in the claim – submitting the non-specific parent “S35.311” without the 7th character extension results in rejection at the clearinghouse level.

Understanding the 7th character: What does “D” mean in S35.311D?

The ICD-10-CM 7th character extension is not a formatting detail – it determines whether a claim passes or fails. For injury codes in chapter S00-T88, the official coding guidelines mandate one of three characters: A, D, or S. Each signals a distinct phase of the patient’s care episode.

The “D” character applies throughout the healing phase, not just at the second visit. A patient attending their sixth post-operative check after portal vein repair surgery still receives the D extension – as long as the original injury remains the subject of active management. For practices handling complex patient records across multiple visits, tracking encounter type in the chart prevents 7th-character errors from cascading into billing denials.

S35.311A vs S35.311D vs S35.311S: Choosing the right code

All three codes describe a laceration of the portal vein. The difference is where the patient sits in their treatment timeline. Selecting the wrong sibling code is one of the most common reasons trauma-related claims are flagged for review.

Portal vein lacerations coded at S35.311S require a separate ICD-10-CM code for the sequela condition itself – the S35.311S code identifies the original injury as the cause, while the late-effect condition (e.g. portal hypertension) gets its own diagnosis code. Practices using structured documentation workflows for vascular trauma codes are less likely to collapse sequela and subsequent-encounter visits into the same encounter type.

Code hierarchy: Where ICD-10 Code S35.311D fits in ICD-10-CM

Every ICD-10-CM code lives inside a layered hierarchy. Understanding the parent chain for ICD-10 Code S35.311D helps coders navigate crosswalks, locate related codes, and verify that the correct chapter rules apply.

• S00-T88 – Injury, poisoning and certain other consequences of external causes (chapter level, non-billable)
• S30-S39 – Injuries to the abdomen, lower back, lumbar spine, pelvis and external genitals (block level, non-billable)
• S35 – Injury of blood vessels at abdomen, lower back and pelvis (category, non-billable)
• S35.3 – Injury of portal or splenic vein (subcategory, non-billable)
• S35.31 – Injury of portal vein (subcategory, non-billable)
• S35.311 – Laceration of portal vein (non-billable parent – requires 7th character)
• S35.311D – Laceration of portal vein, subsequent encounter (billable)

The CDC/NCHS ICD-10-CM web tool lets coders navigate this hierarchy interactively and confirm whether any ancestor node carries Excludes1 or Excludes2 notes that might restrict code use. Always check the full parent chain – restrictions at S35 apply to all child codes including S35.311D.

What is the portal vein? Clinical context for coders

Accurate coding depends on understanding what structure is being described. The portal vein is a large venous vessel that collects nutrient-rich blood from the gastrointestinal tract, spleen, and pancreas and delivers it to the liver for processing before it enters systemic circulation.

• Location: Forms posterior to the neck of the pancreas from the union of the superior mesenteric vein and splenic vein; runs to the liver hilum
• Function: Carries approximately 75% of total hepatic blood flow; major route for absorbed nutrients and gut-derived toxins reaching the liver
• Clinical significance of laceration: Portal vein injuries are high-acuity trauma events associated with significant hemorrhage risk and potential for portal hypertension as a late sequela
• Common causes: Blunt abdominal trauma (motor vehicle collisions), penetrating abdominal injuries, and iatrogenic injury during abdominal surgery

Coders working with abdominal vascular trauma cases should also be familiar with the S35.318 code (other specified injury of portal vein) – used when the injury type is confirmed but does not meet the specific laceration definition. Practices handling trauma documentation across specialties can reduce coding errors with structured digital intake and documentation forms that capture injury mechanism and anatomical location at first presentation.

Approximate synonyms and index references for S35.311D

Medical coders often encounter different terminology in physician notes. These alternate terms all map to ICD-10 Code S35.311D in the alphabetic index and are acceptable clinical descriptions for this diagnosis:

• Portal vein laceration, subsequent encounter
• Laceration of hepatic portal vein, subsequent encounter
• Portal venous injury – laceration type, follow-up visit
• Subsequent care for laceration of portal vein
• Follow-up encounter – portal vein tear

When physician documentation uses any of these phrases, the correct code assignment remains S35.311D provided the encounter meets the definition of active care for an already-treated injury. The AAPC Codify ICD-10-CM lookup lists additional accepted terminology variants for reference. For coding teams managing multiple ICD-10-CM diagnostic codes across different clinical areas, consistent documentation templates reduce synonym-related coding ambiguity.

Excludes notes and coding guidelines for S35.311D

ICD-10-CM coding guidelines carry legal and reimbursement weight. The following notes govern correct use of ICD-10 Code S35.311D and its parent category.

Coding requirements under chapter S00-T88

Chapter S00-T88 injury codes require an external cause code when the mechanism of injury can be identified. While not always mandated for claim payment, including an external cause code (from categories V00-Y99) strengthens documentation and supports medical necessity review. Coders should also apply any applicable 7th character to the external cause code, matching the encounter type assigned to S35.311D.

Sequencing guidance

When a patient presents for aftercare following portal vein laceration repair, S35.311D should be sequenced as the principal or first-listed diagnosis. If the patient also presents with an unrelated condition at the same visit, the coding guidelines for subsequent encounter injury codes allow additional diagnosis codes as appropriate – the injury code does not displace comorbid conditions from the claim. Practices that log structured medical forms for each encounter reduce the risk of missing co-occurring diagnoses at subsequent visits.

Excludes1 and Excludes2 notes

No Excludes1 note applies directly to S35.311D, meaning there is no diagnosis code that can never be reported alongside it by definition. Coders should verify at the S35 category level for any Excludes2 notes (conditions not normally coded together but acceptable when both are documented) that may apply to concurrent abdominal vascular injuries. Per the ICD List reference tool, always verify exclusion notes at every ancestor level in the hierarchy before finalising a claim.

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Code history and annual updates for S35.311D

ICD-10 Code S35.311D has been part of the ICD-10-CM code set since ICD-10-CM was implemented in the United States. The table below summarises the recent version history relevant to FY2026 billing.

Coders should verify active status annually using the official CMS ICD-10-CM tabular list. The code has remained stable across recent fiscal years, but annual review is best practice for any trauma code that may be affected by ICD-10-CM revision cycles. Practices with HIPAA-compliant documentation systems should maintain version-controlled records of which code set was active at the time of each patient encounter.

Related ICD-10 codes for portal vein and abdominal vascular injuries

Portal vein trauma rarely occurs in isolation. Coders handling abdominal vascular injury cases often need to reference sibling and adjacent codes within the S35 category. The table below covers the most frequently cross-referenced codes for surgical and trauma specialties working with abdominal vascular injuries.

When multiple abdominal vessels are injured in the same trauma event, each injured structure receives its own code. Coding guidance from the CMS ICD-10 resource page confirms that multiple injury codes may be reported on a single claim when documentation clearly supports each. Teams managing physical rehabilitation documentation following abdominal trauma will also encounter S35.x codes during coding handoffs from acute care.

Sequela coding with S35.311S: when to use the “S” suffix

Most competitor reference pages describe S35.311D but stop short of explaining S35.311S in clinical depth. This is a genuine content gap: sequela coding for portal vein injuries generates more coder questions than any other aspect of the S35.311 family.

The “S” suffix applies when the original portal vein laceration has fully healed but the patient now presents with a late complication caused by that injury. Portal hypertension is the most common sequela – chronic elevation of pressure in the hepatic portal system resulting from scarring or narrowing at the previous laceration site. Esophageal varices developing months or years after a resolved portal vein injury are another typical S35.311S scenario.

• S35.311S alone is not sufficient – sequela codes identify the originating injury; the sequela condition itself (e.g. K76.6 – portal hypertension) requires its own diagnosis code, listed first
• Active injury and sequela cannot be coded simultaneously – if the original laceration is still under active treatment, use D, not S
• Sequela applies regardless of time elapsed – there is no minimum delay before S can be applied; it is appropriate as soon as the original injury is considered healed and the current presentation is wholly attributable to the late effect
• Documentation must support the causal link – physician notes must explicitly state that the current condition is a sequela of the prior portal vein injury, not an independent new diagnosis

Practices handling complex post-trauma follow-up benefit from structured ICD-10-CM reference workflows that flag encounter type changes – catching the transition from D to S before the claim is submitted rather than after denial. The CDC/NCHS ICD-10-CM tool includes the official tabular list notes for S35.311S that coders should review before assigning this code for the first time.

Conclusion

Portal vein laceration claims fail most often because of 7th character errors – not because the diagnosis is wrong. ICD-10 Code S35.311D is the correct code whenever the patient is receiving active follow-up care for a previously treated portal vein laceration. The distinction from S35.311A and S35.311S is not procedural formality: it determines whether the claim pays or returns for rework.

Pabau’s claims management software helps practice teams build documentation workflows that capture encounter type at the point of care – reducing the 7th-character errors that generate the most preventable denials in trauma coding. To see how Pabau supports accurate ICD-10-CM documentation across your team, book a demo.

Continue your research

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