ICD-10 code S91.122D: Laceration with foreign body of left great toe, subsequent encounter

Key takeaways

S91.122D is the billable ICD-10-CM code for a laceration with a foreign body of the left great toe, without nail damage, at a follow-up visit

The 5th character 2 marks a wound with a foreign body (S91.12). The 6th character 2 marks the left great toe, not a lesser toe

The 7th character D marks a subsequent encounter. Use it for wound checks, dressing changes, and suture removal during healing

Do not switch to S91.112D once the foreign body is removed. The injury code stays the same and only the 7th character changes

Practice management software like Pabau carries claims tools that check code specificity before a claim reaches the payer

ICD-10-CM code S91.122D covers a laceration with a foreign body of the left great toe, without damage to the nail, at a subsequent encounter. You bill it when a patient returns for follow-up care on a big-toe cut that had glass, grit, wood, or metal in it.

Two details in that descriptor cause most of the denials on this code. The foreign body puts the injury in S91.12 rather than S91.11. The digit 2 in the sixth position means the great toe, not toes 2 through 5. Get either one wrong and you have billed a different injury.

This reference covers the full descriptor, the 7th character rules, the code hierarchy, and the sibling codes in S91.12. It also covers documentation requirements, the CPT codes that usually travel with it, and the ICD-9 crosswalk.

S91.122D at a glance

S91.122D is a specific, billable ICD-10-CM code for the current fiscal year. The table below carries the facts coders need before the claim goes out.

Check current billable status in the CDC/NCHS ICD-10-CM web tool before you submit. Code validity changes every October 1.

What is S91.122D? Code definition and clinical meaning

S91.122D describes a laceration of the left great toe that contained a foreign body, with the toenail undamaged, at a follow-up visit during healing. Every part of that descriptor changes the code, so it pays to read it one element at a time.

• Laceration: A wound made by tearing or cutting. Puncture wounds, abrasions, contusions, and open bites all sit in separate S91 subcategories.
• With foreign body: Embedded material was present in the wound, such as glass, grit, wood, metal, or a splinter. This is the 5th character 2, and it separates S91.12 from S91.11.
• Left great toe: The great toe is the hallux, also called the first toe. It is not one of the lesser toes. The 6th character 2 carries both the site and the left side.
• Without damage to nail: The toenail is intact and uninvolved. Nail involvement moves the code into the S91.2 subcategory instead.
• Subsequent encounter: The patient has already had active treatment for this injury and is back for ongoing management while it heals.

The breakdown below maps each character to the detail it carries, and to the code you bill if you misread it.

In day-to-day use, S91.122D lands on wound-check appointments, dressing changes, suture removal, and healing reviews for a big-toe laceration that had something in it. The mechanism is usually stepping on broken glass, a nail, or a metal fragment while barefoot or in open footwear.

Why “with foreign body” decides between S91.11 and S91.12

Embedded material in the wound is what moves a toe laceration out of S91.11 and into S91.12. The two subcategories are otherwise worded identically, which is exactly why they get mixed up.

The foreign body is usually removed at the initial encounter, so the wound is clear by the time the patient returns. The code still stays S91.122D.

ICD-10-CM codes the injury as it presented, and only the 7th character advances through the episode of care. Re-coding the follow-up visit as S91.112D would report a second, different injury to the payer. It also breaks the link between the claim and the initial-encounter claim already on file.

Great toe or lesser toe? The 6th character decides

The 6th character in S91.12 carries the toe and the side together. Great toe and lesser toe are separate values, so a mis-read here bills the wrong anatomy even when the wound type is right.

Every code in that table shares the same wound type: laceration with foreign body, nail undamaged. Only the toe and the side change. The unspecified values, S91.123 and S91.126, invite payer scrutiny, so use them only when the note genuinely does not name the toe.

Understanding the 7th character: Initial, subsequent, and sequela encounters

Every S91.122 claim must carry one of three 7th character values. Per the CMS ICD-10-CM guidelines and code files, the character reflects the phase of care rather than the number of visits.

Critical distinction: Subsequent encounter is not the same as aftercare. Aftercare Z codes apply when the original condition is resolved and the patient needs continued services for something else. While the injury itself is still healing, D is correct.

The 7th character also survives a change of provider. If a patient is repaired in an emergency department and follows up at your practice, your visit is still a subsequent encounter. Encounter-type accuracy is part of routine medical billing hygiene, and it protects the claim on first submission.

S91.122D in the ICD-10-CM code hierarchy

Knowing where S91.122D sits in the tabular list helps you catch specificity errors before submission. The hierarchy runs from a broad category down to the billable code across five levels.

S91.122 without a 7th character is not billable, and payers reject any claim that stops at six characters. S91.122A, S91.122D, and S91.122S are the only valid submissions for this wound type, site, and side.

Related codes in the S91 category

Once the encounter type is settled, the remaining risk is picking a neighboring code by mistake. The table below shows the codes that sit closest to S91.122D and the single detail that separates each one.

Podiatry, sports medicine, and urgent care teams see these codes together in the same wound-management workflow. Comparing siblings side by side in a lookup tool is faster than reading the tabular list. It also catches laterality slips before the claim leaves the practice.

Includes, excludes, and applicable-to notes

The S91 category carries instructional notes that govern when S91.122D can be reported. Read them before you assign any code in this category.

• Code also: Any associated wound infection. Toe wounds that contained a foreign body carry a higher infection risk, so this note fires often on follow-up visits.
• Excludes1, open fracture: An open fracture of the ankle, foot or toes belongs in category S92, with 7th character B added. Code the fracture instead of the open wound.
• Excludes1, amputation: Traumatic amputation of the ankle and foot belongs in category S98. An amputation code and an S91 open wound code for the same site cannot be reported together.
• Applicable to: S91.12 covers lacerations of the toe with a foreign body and an intact nail. The note must support both the foreign body and the absence of nail damage for S91.122D to hold.

Chapter 19 also expects external cause codes where the payer or the guidelines call for them. Those codes matter most at the initial encounter, when the mechanism of injury is documented. At a subsequent encounter they are generally optional unless your payer asks for them.

Documentation requirements for S91.122D

Five elements have to appear in the clinical record to support S91.122D. Miss one and the code is exposed on audit, even when it is clinically correct.

• Laterality: The note states left. “Toe laceration” or “foot wound” with no side named will not support this code.
• Anatomical site: The note names the great toe, the hallux, or the first toe. A reference to a lesser toe or to toes 2 through 5 points to S91.125 instead.
• Foreign body: The record shows embedded material in the wound, and names it where possible. Glass, wood, grit, and metal fragments all qualify. This is usually documented at the initial encounter, so the follow-up note should reference it.
• Nail status: The note confirms the toenail is intact or uninvolved. Documented nail damage moves the code to S91.222.
• Encounter type: The note shows this is not the first visit for the injury. Phrases such as wound check, suture removal, dressing change, or follow-up for laceration all support the D character. Recording the original date of injury helps.

The foreign body element is the one that fails most often. It is captured in the emergency department note and then never repeated, so the follow-up note reads as a plain laceration. Building a wound-detail prompt into your follow-up template fixes that in one step.

CPT codes commonly reported with S91.122D

S91.122D is a diagnosis code, so it needs a procedure code to support the claim. At a subsequent encounter that is usually an established-patient office visit rather than a repair code.

Watch the global period before you bill an office visit at a follow-up. Wound repair codes carry a post-operative period, and a routine wound check inside that window is normally bundled into the repair. Check each code’s global days in the Medicare Physician Fee Schedule and confirm your payer’s own policy.

ICD-9-CM to ICD-10-CM crosswalk for S91.122D

Practices that keep legacy records or reopen historical claims still run into the ICD-9 codes that S91.122D replaced. The General Equivalence Mappings published by CMS give approximate translations only. ICD-9 had no laterality and no encounter-type character, so a single ICD-9 code fans out into many ICD-10 codes.

The ICD-10 transition took effect on October 1, 2015. Confirm any GEM value against the official CMS mapping files before you rely on it for a legacy claim.

Common coding errors and how to avoid them

S91.122D produces a predictable set of denials. Each one below maps to a workflow fix rather than an appeal.

• Coding S91.112D instead of S91.122D: The single most common error on this code. Dropping the foreign body from the descriptor reports a different injury and contradicts the initial-encounter claim already on file.
• Treating the great toe as a lesser toe: S91.122 is the great toe. Coders who read “left toe” as toes 2 through 5 land on S91.125D. Confirm the toe from the note, not from habit.
• Using S91.122A at a follow-up visit: The encounter is D if the patient was already treated for this injury. An A character tells the payer this is the first evaluation, and the claim history contradicts it.
• Submitting S91.122 with no 7th character: The six-character parent is not billable. Saved note templates and code favorites are the usual source of these truncations.
• Applying S91.122S during active healing: Sequela applies only once healing is complete and a late effect appears. While the wound is open, draining, or dressed, D applies.
• Reversing laterality: S91.121D is the right great toe. Side errors surface on payer edits when the claim conflicts with imaging or a prior submission.

Most of these never need to reach the payer. A pre-submission scrub that validates code specificity catches truncated codes and laterality conflicts inside the practice. The clean claim checklist covers the wider set of fields payers expect on a first-pass-accepted submission.

Where to verify S91.122D

Verify the descriptor and the billable status against a primary source every fiscal year. Three references cover it between them.

• CDC/NCHS ICD-10-CM web tool: The official tabular list and index, updated for the current fiscal year.
• CMS ICD-10 code files: The annual code descriptors, the Official Coding Guidelines, and the GEM crosswalk files.
• AAPC Codify entry for S91.122: A quick way to compare the sibling codes in the subcategory side by side.

When a descriptor on a third-party site disagrees with the CDC tool, the CDC tool wins. Third-party lookups lag the October 1 update and occasionally carry stale wording.

How Pabau supports accurate wound coding

S91 coding errors usually surface when the denial arrives. The note is written, the code is picked from memory, and the claim goes out. The payer sends it back weeks later. By then the coder has to reconstruct which toe, which side, and whether material was embedded in the wound.

Practice management software like Pabau moves that check to the point of documentation. Clinical note templates prompt the provider for laterality, the specific toe, foreign body detail, and nail status while the patient is still in the room. The claims management tools then carry an ICD-10 code search, so the coder picks a complete seven-character code rather than typing a truncated one.

Claims are validated before submission and tracked afterwards in one place. Denials come back into the same record as the original note, so the pattern behind them is visible instead of buried in a spreadsheet.

The outcome is fewer reworked claims on injury codes, and less of your coder’s week spent chasing detail that was available at the visit.

Catch coding errors before the payer does

Pabau pairs structured clinical notes with claims management and an ICD-10 code search, so wound codes go out complete and specific the first time. See how it fits your workflow.

Book a demo

Conclusion

S91.122D is the billable ICD-10-CM code for a laceration with a foreign body of the left great toe, nail undamaged, at a subsequent encounter. It holds only when the record confirms four details. Those are the foreign body, the great toe, the left side, and a follow-up visit for an injury already treated.

Two characters do most of the damage on this code. The 5th character separates a wound with embedded material from a clean one. The 6th separates the great toe from toes 2 through 5. Neither is a judgment call, and both are answered by the provider note.

The practices that stop losing money on injury codes do two things. They capture wound detail at the visit, and they validate the code before the claim leaves the building. To see how Pabau handles ICD-10 validation and claim submission for wound codes, book a demo.

Continue your research

Need to understand how claims are processed end to end? Medical claims clearinghouse guide explains how claims move from practice to payer and where ICD-10 code errors get caught.

Handling a denied injury code claim? Denial codes in medical billing covers CARC codes and how to read payer rejection reasons for diagnosis code issues.

Want fewer reworked claims overall? Denial management in healthcare sets out the appeal workflow and the payer patterns behind repeat denials.

Frequently asked questions