ICD code T22.622S – Left elbow second-degree chemical burn, sequela

Key takeaways

T22.622S codes a late effect (sequela) of a second-degree chemical burn of the left elbow, after active treatment and routine healing have ended.

The 7th character S separates sequela from A (active treatment) and D (routine healing). Billing D for a sequela visit is a common denial trigger.

Corrosion codes need a T51-T65 toxic effect code for the chemical and intent. At a sequela visit, that code also takes the 7th character S.

Place of occurrence (Y92) and activity (Y93) codes belong on the initial encounter only, so they aren’t repeated on a T22.622S claim.

Pabau’s claim validation scrubs every claim for missing or invalid details before it leaves Pabau, so fewer sequela claims come back denied.

ICD-10 Code T22.622S: Definition and code breakdown

ICD-10 Code T22.622S is the billable ICD-10-CM code for corrosion of second degree of the left elbow, sequela. It applies when a chemical or caustic burn has healed and the visit treats what it left behind, such as a scar or contracture. The code set is maintained by CMS and the National Center for Health Statistics (NCHS).

T22.622S sits in Chapter 19 (Injury, Poisoning, and Certain Other Consequences of External Causes), block T20-T25, and is valid for the current fiscal year (FY2027). In Pabau’s claims management software, the claim opens pre-filled from the visit’s invoice before it goes to the clearinghouse.

Each character position carries a specific meaning. The table below decodes the full code:

Category T22 covers both burns and corrosions, so the subcategory carries the agent. Thermal injuries at the same site, such as scalds or flame contact, fall under T22.2- rather than T22.6-. For corrosions, the Tabular List adds a “Code first” note: report a T51-T65 toxic effect code to identify the chemical and the intent. The companion codes section below covers it.

What “sequela” means: The 7th character S explained

A sequela is a late effect. It’s a condition caused by a prior injury that remains after the wound has closed and acute treatment has ended. The S in T22.622S tells the payer the corrosion itself is no longer being treated. The visit addresses what it left behind, such as a hypertrophic scar, a contracture, or a chronic wound complication.

Payers read that character closely. Under the ICD-10-CM Official Guidelines, a sequela visit carries two codes. The code for the residual condition, such as a scar contracture, comes first. T22.622S follows it to identify the original injury.

Three clinical scenarios help distinguish the characters:

• Active treatment (A): A patient presents to the ED with a fresh acid splash on the left elbow. The wound is open, blistering, and being actively managed. Use T22.622A.
• Routine healing (D): The same patient returns two weeks later for a wound check. The burn is healing as expected, with no complications. Use T22.622D.
• Sequela (S): Six months after the burn healed, the patient returns with a tight scar contracture at the elbow that limits range of motion. The contracture is the reason for the visit. Use T22.622S alongside the contracture or scar code.

T22.622A vs T22.622D vs T22.622S: Choosing the right 7th character

The three 7th character variants of T22.622 are often confused, and picking the wrong one is a frequent cause of denials on corrosion sequela visits. The table below maps each character to its clinical trigger and the documentation clues to look for:

A practical rule helps here. When the note records a history of chemical burn and the chief complaint is scarring, restricted movement, or chronic skin changes, S applies. If the wound is still present and under treatment, use A for active treatment or D for a routine healing follow-up.

Related and neighboring codes to know

Selecting the wrong code within category T22 is usually a laterality, depth, or agent error. The table below shows the codes most often confused with T22.622S:

For crosswalk reference, the approximate ICD-9-CM equivalents fall within the 940-949 burn series. ICD-9 captured neither the chemical vs thermal distinction nor laterality, so any mapping to T22.622S is non-specific.

Use crosswalks for legacy audits only, never for active claim submission. The AAPC Codify ICD-10-CM lookup supports code-to-code crosswalk searches.

Companion codes to report with T22.622S

Corrosion codes in category T22 carry a “Code first” note in the ICD-10-CM Tabular List. At a sequela visit, a T22.622S claim usually carries three diagnosis codes:

• The residual condition: This is the code for what is being treated now, such as L90.5 for scar conditions of the skin. Under the sequela guideline, it’s listed before T22.622S.
• A toxic effect code (T51-T65): This identifies the chemical and the intent, and it takes the 7th character S at a sequela visit. For an accidental acid burn, that’s T54.2X1S. Alkalis use T54.3X1S.
• T22.622S itself: This identifies the original injury by depth, site, and side.

Place of occurrence (Y92) and activity (Y93) codes work differently. Both are reported once, at the initial encounter, and carry no 7th character. Take Y93.H9 (other activity involving exterior property and land maintenance, building and construction). It belongs on the T22.622A claim from the first visit. It isn’t repeated at a sequela visit.

A missing toxic effect code, or Y92 and Y93 codes copied forward from the first visit, are avoidable errors on these claims. Checking companion codes before submission is a core step in medical billing compliance.

Clinical documentation requirements for T22.622S

Five documentation elements must appear in the provider note to support T22.622S without triggering a denial or audit flag:

1. Laterality confirmed as left: The note must state “left elbow” explicitly. “Elbow” without a side defaults to T22.629S, which payers that require specific laterality may reject.
2. Site specificity: “Elbow” is the required site. “Forearm” maps to T22.61- and “upper arm” maps to T22.63- instead.
3. Degree documented as second: The note must describe second-degree features, such as blistering, partial thickness, or dermal involvement, or state “second-degree corrosion.” First degree (erythema only) maps to T22.522S. Third degree (full-thickness destruction) maps to T22.722S.
4. Nature of the agent confirmed as chemical or caustic: The original injury note or the history section should name the caustic or chemical agent. Thermal injuries use the T22.2- series.
5. Sequela status documented: The current note must make clear the visit treats a late effect of a prior corrosion. An active or healing wound does not qualify. Phrases such as “residual scarring from prior chemical burn” or “post-corrosion contracture” support the S character. A note that only describes an open wound contradicts sequela coding.

The chart below shows where the code moves when any one of those five answers changes.

Practices that run a structured medical billing workflow can build these five elements into intake and note templates. That way, they’re in the record before the claim is generated.

Payer requirements and common claim denial reasons for T22.622S

Medicare, Medicaid, and commercial payers treat sequela burn and corrosion codes as clinically distinct from acute or healing-phase injury codes.

For a sequela visit, payers generally expect T22.622S to sit beside a procedure that treats the late effect. That means skin grafting, scar revision, or occupational therapy for contracture, for example.

A sequela diagnosis paired with a wound-care procedure code is a mismatch, since wound care is more typical of D-character visits. It often triggers a medical-necessity review or an outright denial.

These are the most frequent denial reasons for T22.622S claims, and how to address them:

Systematic denial management for sequela corrosion claims starts with tracking denial reason codes by category. Repeated T22.6- sequela denials often trace back to one upstream cause, such as a note template with no late-effect language. Reviewing denial codes tells you whether a denial is a coder, documentation, or payer-policy issue before you appeal.

Reconstructive procedures billed with a T22.622S diagnosis may need prior authorization from Medicare Advantage and commercial plans. Check the applicable local coverage determination (LCD) for wound-related reconstructive services before scheduling.

Submitting a clean claim from the outset avoids the delays that come with authorization requests after submission. That means all companion codes, the supporting documentation, and the correct procedure-diagnosis pairing.

How Pabau helps T22.622S sequela claims go out clean

Many sequela denials start before the claim is ever sent. A coder picks D instead of S, or the toxic effect code never reaches the claim. The error only surfaces when the payer rejects it, weeks later.

In Pabau, the claim opens pre-filled from the visit’s invoice. Claim validation then scrubs every claim for missing or invalid details before it leaves Pabau. If a claim still comes back rejected, Pabau flags it as Needs action and links straight to the field that needs correcting.

US practices send CMS-1500 claims through Claim.MD to thousands of US payers. Your team can check insurance eligibility before the visit. Payments then settle straight from electronic remittance advice (ERA) files, so less of the week goes into matching payments by hand.

Reduce sequela claim denials with Pabau

Pabau’s claim validation scrubs every claim for missing or invalid details before it leaves Pabau. Book a demo to see how it catches errors on injury and sequela claims before the payer does.

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Conclusion

T22.622S turns on one question asked at every elbow follow-up. Has the wound healed, and is the visit treating what it left behind? If yes, S applies, alongside a toxic effect code that also ends in S.

Put that question into your note template and the claim follows from the documentation. Leave it out, and every sequela claim depends on a coder reading between the lines.

Pabau’s claim validation scrubs every claim for missing or invalid details before it leaves Pabau. Book a demo to see how it keeps your sequela claims moving from note to payment.

Continue your research

Need to understand how clearinghouse submission works? Claim.MD clearinghouse overview explains how electronic claims reach payers and what the adjudication process involves.

Tracking ERA remittances after submission? Electronic remittance advice (ERA) explained covers how 835 remittance files map denial reason codes back to specific claims.

Building a denial prevention workflow? Insurance eligibility verification guide walks through pre-claim eligibility checks that catch coverage problems before T22.622S claims are submitted.

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