ICD code S31.147D – Left flank puncture wound with foreign body, follow-up

Key takeaways

S31.147D covers follow-up care for a left flank puncture wound with a foreign body. Use S31.147A for the first active-treatment encounter.

The 5th character 4 confirms a foreign body. With no documented foreign body, use S31.137D instead.

The 6th character 7 means the left flank, not the left lower quadrant. A left lower quadrant wound takes S31.144D.

If the note gives no quadrant or flank, the fallback is S31.149D. A flank with no side documented takes S31.14AD.

Pabau’s claims management software pairs S31.147D with matching CPT codes and flags missing documentation before submission.

ICD-10 Code S31.147D: Definition and code components

ICD-10 Code S31.147D is a valid, billable ICD-10-CM code for follow-up care of a left flank puncture wound with a foreign body. Its full official descriptor is: Puncture wound of abdominal wall with foreign body, left flank without penetration into peritoneal cavity, subsequent encounter.

The code sits in Chapter 19 of the CDC/NCHS ICD-10-CM tabular list (Injury, Poisoning and Certain Other Consequences of External Causes, S00-T88). Its category is S31, which covers open wounds of the abdomen, lower back, pelvis, and external genitals.

What “subsequent encounter” means for S31.147D

The 7th character “D” designates a subsequent encounter. Per the ICD-10-CM Official Guidelines for Coding and Reporting, that means the visit takes place after active treatment for the injury is complete.

Three 7th character options govern injury codes in this category:

• A (initial encounter): Use while the patient is receiving active treatment for the injury. This includes the ED visit and the first visit where the wound is irrigated and the foreign body located or removed.
• D (subsequent encounter): Use for visits after active treatment, during the healing or recovery phase. Wound checks, suture removal, and dressing changes after foreign body removal all fall here.
• S (sequela): Use when the encounter treats a late effect of the original injury, such as a scar.

The most common coding error is applying “A” to every visit in the treatment timeline. Once active treatment is complete, coders switch to “D” for routine follow-up encounters, even if the patient is still symptomatic. Using “A” on a return wound-check visit is a coding inaccuracy that can draw payer audit attention.

Clinical scenarios: When to use S31.147D

S31.147D applies when a patient returns for follow-up care after active treatment for a puncture wound with a foreign body in the left flank. The flank is the side of the trunk between the lower ribs and the hip.

Three worked scenarios illustrate appropriate use:

1. Wound check after ED visit: A patient arrives in the ED with a glass fragment embedded in the left flank. The ED physician irrigates the wound, removes the fragment, and closes it, which is coded S31.147A. A week later the patient returns for a wound check and suture removal, which is coded S31.147D.
2. Monitoring visit after removal: A worker sustains a metal splinter puncture to the left flank, and the fragment is removed under local anesthetic. That encounter is S31.147A. The later visits to monitor healing and change dressings are S31.147D.
3. Follow-up with a new complaint: A patient had a wooden foreign body removed from the left flank. Three days later they return with redness and swelling at the site. Code the visit S31.147D, and code the wound infection as well, as the S31 “Code also” note directs.

Inclusion and exclusion notes for open wound abdominal wall codes

The S31 category and the S31.1 subcategory carry scope notes in the CDC tabular list. Check them before assigning S31.147D.

What S31.147D includes

• Traumatic puncture wounds of the abdominal wall with a documented embedded, retained, or removed foreign body
• Wounds located in the left flank, without penetration into the peritoneal cavity
• Encounters in the subsequent, aftercare phase, after active treatment is complete

What S31.147D excludes

• Excludes1 (never code together): Traumatic amputation of part of abdomen, lower back and pelvis (S38.2-, S38.3).
• Excludes2 (report both if both are present): Open wound of hip (S71.00-S71.02) and open fracture of pelvis (S32.1- to S32.9 with 7th character B).
• Excludes2 at S31.1: Open wound of abdominal wall with penetration into the peritoneal cavity (S31.6-). A penetrating left flank puncture with a foreign body is S31.647D at follow-up.
• Code also: Any associated spinal cord injury (S24.0, S24.1-, S34.0-, S34.1-) and any wound infection.
• Note: A left flank puncture wound without a foreign body uses S31.137D. Code selection depends on provider documentation, not coder inference.

Commonly confused codes: S31.147D vs similar ICD-10 codes

Six codes are routinely confused with S31.147D. The table below shows where each one differs.

The most frequent site mix-up is S31.147D vs S31.144D. Both describe a left-sided puncture wound with a foreign body, but 7 is the left flank and 4 is the left lower quadrant. The flank sits on the side of the trunk, while the lower quadrant sits on the front of the abdomen.

The most frequent detail mix-up is S31.147D vs S31.137D. The 5th character decides it: 4 means a foreign body is documented, and 3 means there is none. Coders cannot infer a foreign body from the wound description alone, so the provider note must state it.

The decision path below runs the three checks in the order a coder should make them.

Documentation requirements for S31.147D

Using S31.147D without adequate supporting documentation is a common payer denial trigger. The clinical note should support every element of the code before the claim goes out.

The provider note must confirm all five of the following:

• Wound type: The note must say “puncture wound,” not “laceration,” “abrasion,” or “cut.” These terms carry different code assignments, so “laceration with foreign body” points to a different code.
• Foreign body confirmation: The provider must document the foreign body, whether embedded, retained, or already removed. Imaging reports and procedure notes count, but a coder cannot assume a foreign body from the clinical picture.
• Anatomical site: The note must name the left flank of the abdominal wall. If it only says “abdomen” or “abdominal wall,” the coder falls back to S31.149D, the unspecified quadrant code.
• Laterality: The side matters as much as the site. A flank wound documented without “left” or “right” is coded S31.14AD, the unspecified flank code.
• Encounter phase: The note must support a subsequent, aftercare visit. Terms such as “follow-up,” “wound check,” “suture removal,” or “dressing change” show that active treatment has already occurred.

If the wound type itself is not documented, the code moves out of the puncture subcategory altogether. An unspecified open wound of the left flank is S31.107D, and one with no site at all is S31.109D.

Payer requirements and prior authorization for subsequent wound encounters

Subsequent encounter codes like S31.147D generally do not need prior authorization for routine wound care. Payers still apply several claims-processing checks that decide whether the claim pays on first submission. Good medical billing fundamentals account for these before the claim goes out.

• Continuity with the initial encounter: Many payers expect a prior claim carrying S31.147A before they process a subsequent encounter for the same injury. A “D” code with no initial encounter on file is a common denial trigger. If the first visit was before October 1, 2026, the initial claim will carry the code valid on that date, not S31.147A.
• Consistent use of “D” across follow-up visits: Once you apply “D,” later aftercare visits for the same injury carry it too. Only a late effect calls for “S.” Switching back to “A” mid-course raises a payer flag.
• Local Coverage Determinations (LCDs): Wound care services such as debridement may fall under Medicare contractor LCDs. Check your Medicare Administrative Contractor’s wound care LCD, because coverage criteria and CPT lists vary by region. The CMS ICD-10 codes page carries the current code files and coding guidance.
• CPT and ICD-10 linkage: Payers check that the billed procedure makes clinical sense for the diagnosis. Bill a foreign body removal CPT such as 10120 only if a foreign body was removed at that visit.

For practices with a high volume of wound care claims, claims management software that validates CPT-ICD linkage before transmission cuts first-pass denials. Pabau, the practice management platform we build, submits claims electronically through Claim.MD and runs those checks before the claim leaves the practice.

CPT codes commonly paired with S31.147D

The procedure billed alongside S31.147D must match what was documented and performed at the subsequent encounter. The table below shows the most frequently paired CPT codes by service type.

CPT selection depends on what the provider documented and performed, not on the ICD-10 diagnosis alone. A fragment lodged in muscle is billed with 20520 rather than 10120. Debridement at the follow-up visit is billed with 97597, plus 97598 for each additional 20 sq cm.

Use the AAPC ICD-10-CM lookup for crosswalk checks, and confirm each pairing against National Correct Coding Initiative (NCCI) edits.

Common claim denial reasons for S31.147D

S31.147D denials follow predictable patterns. Knowing them before submission reduces rework and protects reimbursement timelines.

1. No corresponding initial encounter on file: The payer has no record of S31.147A for this injury. Fix: confirm the initial encounter claim was submitted before sending follow-up claims. If another facility treated the injury first, say so in the claim notes. If the first visit was before October 1, 2026, the initial claim will carry the code valid on that date, not S31.147A.
2. Foreign body not documented: The note describes a puncture wound but never confirms a foreign body. The payer denies or recodes to S31.137D. Fix: ask the provider to amend the note with explicit foreign body status before resubmitting.
3. Site documented as left lower quadrant or left abdomen: A left lower quadrant wound is S31.144D, and a vague site falls back to S31.149D. Fix: query the provider to confirm the wound is in the left flank. Site specificity is part of submitting a clean claim, and payers routinely flag it on wound care codes.
4. CPT/ICD-10 mismatch: A foreign body removal CPT such as 10120 is billed at a visit where only a dressing change was performed. Fix: align CPT selection with the documented service before submission.
5. Sequela (S) used instead of subsequent encounter (D): S31.147S on a routine aftercare visit draws payer flags. Use “S” only when the visit treats a late effect of the injury, such as a scar.

A structured denial management workflow that logs these five denial types speeds up appeals. It also shows whether the cause is documentation, coding, or CPT selection. Knowing the denial codes in medical billing behind each rejection tells you which fix applies before you appeal.

How Pabau supports wound care billing workflows

Wound care follow-ups generate many ICD-10 selections where one wrong character becomes a denied claim. A flank coded as a quadrant, a missing foreign body note, or the wrong encounter letter is enough. Pabau’s claims management tools connect clinical documentation to billing so coders can check both before submission.

Through Pabau’s integration with the Claim.MD clearinghouse, practices get real-time eligibility checks, built-in CPT and ICD-10 catalogs, electronic 837P claim transmission, and ERA/835 remittance processing. For high-volume wound care practices, S31.147D claims go out with the supporting CPT already validated, without adding manual review steps.

Reduce wound care claim denials from the first submission

Pabau pairs ICD-10 codes with the right CPT codes, runs real-time eligibility checks, and submits claims through Claim.MD. Your S31.147D follow-up claims go out clean.

Book a demo

Conclusion

S31.147D rewards precise notes and punishes assumptions. The 6th character 7 means the left flank, so a wound on the front of the lower abdomen belongs to S31.144D instead. Build the site, the foreign body status, and the follow-up wording into your wound care templates, and the code assigns itself correctly.

Pabau’s claims management and Claim.MD integration give wound care billing teams a pre-submission check that catches CPT/ICD mismatches before the payer does. To see how it works in practice, book a demo with the Pabau team.

Continue your research

Need to understand how clearinghouse submissions work? Medical claims clearinghouse guide explains how electronic claim routing and ERA processing reduce denial rates.

Want to understand the full revenue cycle behind these claims? What is revenue cycle management covers how coding accuracy connects to cash flow for clinical practices.

Looking for a structured wound care superbill reference? Superbill guide walks through how to build a compliant superbill that supports ICD-10 code specificity requirements.

Frequently asked questions