ICD code S91.211D – Laceration of right great toe with nail damage

Key takeaways

S91.211D is a fully billable ICD-10-CM code valid for FY2026, specific to the right great toe with nail involvement.

The 7th character D marks the healing phase of care, which can run across many follow-up visits.

Without documented nail damage in the chart note, the correct code drops to S91.111D.

S91.211D needs a paired wound care CPT code, because the diagnosis alone does not justify a claim.

Practice management software like Pabau flags laterality mismatches and 7th-character errors before submission.

ICD-10 Code S91.211D: Quick reference

ICD-10 Code S91.211D sits within the S90-S99 chapter (Injuries to the ankle and foot) under category S91 (Open wound of ankle, foot and toes).

The table below captures the core reference data coders need before submitting a claim. Confirm the code is active for the date of service using the CDC/NCHS ICD-10-CM web tool.

What does S91.211D mean? Decoding the code structure

S91.211D describes a laceration without foreign body of the right great toe with damage to nail. Each character carries a distinct clinical meaning, and together they decide whether the claim passes payer edits. Reading the structure also makes it easier to pick the right adjacent code when the documentation is thin.

Without foreign body means the wound is a clean laceration with no retained material. If a foreign body was removed at the initial visit, later follow-up visits still use the “without foreign body” code, provided the documentation confirms removal. Damage to nail means the nail plate, nail bed, or nail fold is involved, either disrupted or at risk. If the note describes periungual involvement, that satisfies this qualifier. Laterality is non-negotiable: S91.211D applies strictly to the right great toe. A left-toe laceration with nail involvement is S91.212D.

Understanding the 7th character D: Subsequent encounter defined

The 7th character D means the patient has already had definitive treatment for this wound. The visit being billed falls in the healing or recovery phase, per the ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a. This is the most misunderstood rule in injury coding, and it drives the most auditable billing errors on open-wound claims.

What “subsequent” does NOT mean: it does not mean the second visit. Take a patient who receives wound irrigation, debridement, and primary closure at the emergency department on day one. That visit sits in the initial encounter phase, and the wound takes 7th character A on that claim. Every follow-up wound check afterward uses character D, whether it is the second visit or the tenth. The calendar date does not decide the character. The phase of care does.

S91.211D vs S91.211A vs S91.211S: Choosing the right 7th character

All three codes describe an identical anatomical wound and differ only in the phase of care. That is why the wrong 7th character is both common and easily flagged by payer claim-edit systems. Using A for a routine wound check is one of the most auditable coding errors on open-wound claims, according to AAPC coding guidance.

Adjacent and commonly confused codes

Selecting the wrong code from the S91.2xx cluster is a documentation-driven error. The most common misses involve failing to specify laterality, nail involvement, or the presence of a foreign body. Use AAPC’s ICD-10-CM lookup alongside the chart notes to confirm all five code components before submitting.

What the chart note must document

The chart note must support every component of the code at the specific encounter being billed. Incomplete documentation forces a downgrade to a less-specific code, which pays less and gives an auditor something to pull on. Match each of the code’s five components to explicit language in the note before the claim goes out.

• Laceration confirmed: The note must state “laceration” explicitly. Abrasion, puncture, and contusion are separate wound types that map to different codes. The wound description cannot be ambiguous.
• No foreign body documented: Either the note confirms none was found at the initial visit, or it records removal at an earlier encounter. If a foreign body remains, S91.221D applies.
• Right great toe site: Laterality (right) and anatomical specificity (great toe, not “toe” or “foot”) must appear in the note. A note that says “left toe” when you have billed S91.211D is a laterality mismatch – one of the top denial triggers.
• Nail involvement: The note must describe damage, disruption, undermining, or involvement of the nail plate, nail bed, or nail fold. “Periungual swelling” without explicit nail involvement may not be sufficient for this qualifier.
• Subsequent encounter context: The note should reflect a follow-up or wound-check visit, not a first-time evaluation or an acute intervention requiring definitive repair.

When nail damage is not explicitly documented, the clinically appropriate code becomes S91.111D, which covers the same right great toe laceration without nail involvement. Querying the treating provider for clarification beats assuming the nail was involved. The matrix below shows how three documented facts separate the four codes a coder is choosing between.

Payer requirements and pre-authorization

Medicare and most commercial payers expect S91.211D to travel with a wound care procedure code. The diagnosis on its own does not establish medical necessity without a linked service. According to CMS ICD-10 coding guidance, diagnosis codes must be linked to procedures that reflect the service rendered. For a subsequent wound care encounter, the CPT code chosen has to match what the note documents.

• Medicare: Local Coverage Determinations (LCDs) for wound care services set the medical necessity bar. MAC policies vary, so verify the applicable LCD before billing repeated subsequent encounters. The healing timeline must be documented if visits extend beyond the expected recovery window.
• Commercial payers: Many require documentation that the wound is progressing toward closure. A note showing static or worsening wound status without a treatment plan adjustment may trigger a medical necessity denial.
• Medicaid: Policies vary by state. Some state Medicaid programs require prior authorization for wound care beyond a set number of visits. Verify with the state-specific Medicaid portal before the second or third subsequent encounter visit.
• Prior authorization: Routine wound checks for an uncomplicated toe laceration typically do not require pre-authorization. However, if the service paired with S91.211D escalates to surgical debridement, authorization requirements differ by payer.

CPT codes commonly paired with S91.211D

S91.211D must link to a procedure code that reflects the service documented at the subsequent encounter. The diagnosis code answers why the patient was seen, and the CPT code answers what was done for them. Selective debridement billed as 97597 is the most frequent pairing at a wound care follow-up, and it carries documentation requirements of its own.

Common claim denial reasons for S91.211D

Denials on S91.211D cluster around three failure points. The encounter type is wrong, the nail documentation is missing, or the CPT and ICD codes do not agree. Each failure carries a distinct remark code, and tracing the remark back to the coding error beats resubmitting the same claim unchanged. Our reference on denial codes explains what each payer remark is telling you.

How Pabau keeps 7th-character and laterality errors off your claims

A coder working from a printed superbill cannot see that the note says left toe while the claim says right. The mismatch surfaces weeks later as a denial with a remark code attached, and by then the wound check is long finished.

Pabau, practice management software for busy practices, keeps the chart note and the claim in one record. When a wound care visit is coded, the diagnosis, the laterality and the encounter type all read from what the clinician documented. Our claims management software then checks the diagnosis against the paired CPT code before the claim leaves the practice.

For a practice running weekly wound checks, that means fewer resubmissions on injury codes and a shorter path from the visit to the payment.

Reduce claim denials on injury codes

Pabau’s built-in claims management tools flag 7th-character mismatches, laterality errors, and CPT-ICD misalignments before your claims reach the payer. See how practices reduce open-wound denials with smarter pre-submission checks.

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Conclusion

Accurate use of ICD-10 Code S91.211D rests on three habits. Apply the correct 7th character from the first follow-up visit. Confirm nail involvement in the note before coding. Then pair the diagnosis with a CPT code that matches the service. Get those three right and the code rarely gives trouble.

The two denials that cost the most on this code are wrong encounter type and laterality mismatch. Both are caught at review, by someone reading the note against the claim, which makes them a workflow problem rather than a coding one. Book a demo to see how Pabau runs that check on injury codes across a multi-provider practice.

Continue your research

Need to understand how claim edits catch coding errors before adjudication? Clean claim submission best practices walks through the pre-submission checks that keep wound care claims out of the denial queue.

Want to decode denial remark codes after a rejected S91.211D claim? Denial management in healthcare covers how to categorize, track, and resolve CARC-coded rejections systematically.

Looking for the remark codes on a claim that has already been adjudicated? Electronic remittance advice explains how to read an ERA and pull the denial reason for each line.

Building a documentation standard your coders can audit against? Medical billing compliance sets out the note requirements that keep injury coding defensible.

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