ICD-10 Code T31.52: Burns involving 50-59% of body surface

Key takeaways

ICD-10 Code T31.52 describes burns involving 50-59% of total body surface area (TBSA) with 20-29% third-degree burns – a billable, specific code valid for HIPAA-covered transactions.

T31.52 became effective October 1, 2025 under the 2026 ICD-10-CM edition and is typically assigned alongside site-specific burn codes (T20-T25), not as a standalone principal diagnosis.

The Rule of Nines is the standard tool for estimating TBSA in adult patients – coders must confirm both the total burn percentage and the third-degree sub-percentage are explicitly documented to support T31.52.

Pabau’s digital clinical forms help burn care teams capture TBSA percentage, burn depth, and site-specific codes at the point of care, supporting accurate coding downstream.

ICD-10 Code T31.52: Definition and billable status

Most burn coding errors surface at the point of code selection, not during claim submission. When a patient presents with burns covering more than half their body, coders need to confirm two separate percentages before assigning any T31 code.

The first is the total body surface area (TBSA) burned, and the second is the proportion of that area that is third-degree. ICD-10 Code T31.52 captures one specific combination of those two figures.

T31.52 is a billable, specific ICD-10-CM code valid for use in HIPAA-covered transactions. It describes burns involving 50-59% of body surface with 20-29% third-degree burns. The 2026 edition became effective October 1, 2025.

Coders working with digital clinical forms for burn patients can build intake workflows that capture both percentages at the encounter level. That reduces the back-and-forth between clinical staff and coders before claim submission.

T31.52 code at a glance

The table below summarizes every field a coder or billing professional needs to confirm before submitting T31.52 on a claim.

The CDC/NCHS ICD-10-CM web tool allows coders to verify the current edition year and tabular hierarchy for T31.52 directly from the authoritative US source.

Understanding total body surface area burns

Total body surface area (TBSA) is the foundational concept behind every T31 code. Burns are rarely confined to a single anatomical region. Clinicians and coders need a standardized way to measure how much of the body is affected.

The T31 category classifies burns strictly by extent, expressed as a percentage of TBSA. T31.52 falls in the T31.5 subcategory, meaning the total burned area covers between 50% and 59% of the patient’s body surface.

This threshold is clinically significant. The American Burn Association classifies burns at or above 20% TBSA as major burns. That classification triggers fluid-resuscitation protocols and criteria for transfer to a verified burn center.

The Rule of Nines: Calculating burn extent

The Rule of Nines is the standard tool for estimating TBSA in adult burn patients. It assigns a fixed percentage to each major body region so that clinicians can rapidly tally total burn coverage at the bedside.

Reaching 50-59% TBSA typically involves burns across multiple major regions – both legs plus the trunk, for instance. As for pediatric patients, the Lund-Browder chart is more accurate because children have proportionally larger heads and smaller lower extremities than adults. Coders should confirm which assessment method was documented when reviewing pediatric burn records.

An occupational therapy platform documents how a patient regains function after the injuries these codes describe.

Third-degree burns: what the 20-29% specifier means

The second number in T31.52 matters as much as the first. Burns at the 50-59% TBSA threshold can involve varying proportions of full-thickness, or third-degree, injury. The ICD-10-CM T31.5 subcategory uses a second digit to capture that breakdown.

Third-degree burns destroy all layers of the skin through the epidermis and the full dermis, often extending into subcutaneous tissue. They are painless at the wound site because nerve endings are destroyed, and they require surgical debridement and skin grafting rather than conservative wound management.

The 20-29% third-degree specifier in T31.52 indicates that between one-fifth and just under one-third of the patient’s total burned area is full-thickness injury.

• T31.50 – 50-59% TBSA, with 0-9% third degree burns
• T31.51 – 50-59% TBSA, with 10-19% third degree burns
• T31.52 – 50-59% TBSA, with 20-29% third degree burns
• T31.55 – 50-59% TBSA, with 50-59% third degree burns (full-thickness throughout)

Selecting the wrong fourth character here is one of the most common claim-level errors in burn coding. If the physician documents 25% third-degree burns out of 55% total, the correct code is T31.52, not T31.50 or T31.59.

Where T31.52 fits in the T31 burn code family

T31.52 sits within the T31 category, which classifies burns exclusively by body surface extent. Understanding where T31.52 falls in the broader T31 family helps coders quickly confirm they have the most specific available code. For a code at the opposite end of the TBSA range, see T31.94.

T31 vs T32: Burns vs corrosions

T31 and T32 look identical in structure, but they classify two different injury mechanisms. Code T31 covers burns caused by thermal sources (fire, heat, hot liquids, radiation, electricity, and friction). T32 covers corrosions caused by chemical agents.

Both categories use the same TBSA subclassification system, so the codes are structurally parallel. T32.52 would describe chemical corrosions covering 50-59% TBSA with 20-29% third-degree corrosion – the same extent thresholds, different injury type.

Coders should confirm the burn cause from the clinical notes before selecting between T31 and T32. Per the CMS ICD-10 coding guidelines, the cause of the injury drives the parent category selection.

Documentation requirements for T31.52

A claim submitted with T31.52 will face scrutiny if the underlying medical record does not support both percentage figures. Reviewing medical documentation in healthcare standards confirms that specificity is the central requirement: vague descriptors like “extensive burns” do not map to this code.

The record must explicitly document all of the following to support T31.52:

• Total TBSA percentage – a documented figure between 50% and 59%, with the assessment method noted (Rule of Nines for adults; Lund-Browder for pediatric patients)
• Third-degree burn percentage – a documented figure between 20% and 29% of total TBSA, separately stated from the overall burn extent
• Burn cause – thermal source confirmed (to distinguish T31 from T32 corrosion codes)
• Anatomical sites affected – to support the companion site-specific codes (T20-T25 range) assigned alongside T31.52
• Burn depth at each site – first, second, and third-degree areas identified separately in the clinical notes

Practices using clinical records management software can structure burn encounter templates to prompt clinicians for each of these data points before the note is finalized. This avoids the common downstream problem of a coder finding a TBSA figure but no documented third-degree percentage. The same specificity principle applies to T31.32 as well.

ICD-10-CM coding guidelines and sequencing for T31.52

The ICD-10-CM Official Guidelines for Coding and Reporting (Section I.C.19.d) set out the sequencing logic for burn codes. These rules determine whether T31.52 is listed as the principal diagnosis or as an additional code. That distinction affects DRG assignment and reimbursement. The same sequencing logic applies to T31.11 as well.

Practices that use claims management software can build coding queues that flag burn encounters for sequencing review before submission.

• Inpatient admissions for burn treatment: The burn with the highest degree of severity is sequenced as the principal diagnosis. T31.52 is used as an additional code to convey the extent of involvement.
• Outpatient/ambulatory encounters: The site-specific burn code (e.g. T22.39XA for third-degree burn of the shoulder) is typically listed first, with T31.52 as an additional code for extent.
• Multiple burn sites: Sequence the most severe burn first. When multiple sites have different depths, the site with the highest depth drives the principal code.
• Seventh-character requirement: Site-specific T20-T25 burn codes require a seventh character indicating encounter type: A (initial), D (subsequent), S (sequela). T31.52 itself does not require a seventh character.

The AAPC ICD-10-CM code lookup allows coders to cross-reference T31.52 alongside related site-specific codes and confirm the current coding guidelines for each.

Codes used alongside T31.52

T31.52 is rarely the only code on a burn claim. The table below shows the main code categories assigned with it. Good healthcare compliance for billing means confirming that every companion code has supporting documentation. Practices can also use patient health record tools during the documentation and transmission process.

Approximate synonyms and index references

The ICD-10-CM alphabetical index and tabular list include several approximate synonyms for T31.52. These are the clinical descriptors coders may encounter in physician notes that map to this code:

• Burns of 50-59% body surface area with 20-29% third-degree burns
• Burns involving fifty to fifty-nine percent of body surface with twenty to twenty-nine percent third degree
• Major burns, 50-59% TBSA, 20-29% full-thickness
• Flame burns, 50-59% total body surface area, 20-29% deep burns

When a physician documents “approximately 55% of body surface area burned with about 25% full-thickness injury,” the coder maps to T31.52. Both described values fall within the 50-59% and 20-29% ranges.

Clinical context: Who is coded with T31.52?

Burns at the 50-59% TBSA threshold with 20-29% third-degree involvement represent one of the most resource-intensive injury presentations in acute care. Clinicians and coders encounter T31.52 in specific, predictable settings.

Facilities managing this population need documentation and billing processes that handle the complexity of multi-site, multi-depth burn injuries.

T31.52 is most commonly assigned for patients in these clinical contexts:

• Burns unit admissions: Patients with 50-59% TBSA burns almost always require hospital admission. The T31.52 code appears alongside inpatient encounter codes and site-specific burn codes across multiple anatomical zones.
• Surgical grafting cases: 20-29% third-degree injury means significant full-thickness loss requiring skin grafting. Teams running plastic surgery EMR software can track graft procedures and outcomes alongside the underlying burn diagnosis.
• Fluid resuscitation management: The Parkland formula uses TBSA to calculate initial IV fluid requirements. Proper TBSA documentation (which underpins T31.52 assignment) is clinically necessary, not just a billing requirement.
• Transfer cases: Patients presenting to a community hospital before transfer to a specialist burn center may have T31.52 assigned at the originating facility. Continuity of coding matters at the receiving site too.

For practitioners documenting these cases, HIPAA-compliant patient documentation practices are essential when transmitting burn records between facilities. See HIPAA-compliant patient documentation for guidance on secure record transfer requirements. The ResDAC guide to ICD codes in Medicare files also explains how burn diagnosis codes flow through Medicare claims data for multi-facility episodes.

Related ICD-10 codes

• ICD-10 code T84.119D — Broken internal fixation device
• ICD-10 Code T31.85 — Burns involving 80-89% body surface area
• ICD-10 Code T31.91 — 90%+ TBSA, 10-19% third-degree burns

How Pabau supports burn care documentation and coding

Burn units handling T31.52-level injuries track TBSA percentages, third-degree sub-percentages, and multiple site-specific codes for every encounter. When that detail lives only in free-text physician notes, coders spend time chasing missing figures instead of assigning codes.

Pabau’s digital clinical forms let burn units build structured encounter templates. Each template prompts for total TBSA, third-degree percentage, and anatomical site at the point of care. Practices can also flag which fields are missing before the note is finalized, rather than after a coder has already opened the chart.

The result is fewer round-trips between clinical staff and coders, faster code assignment, and documentation that supports T31.52 before a claim ever reaches billing.

Streamline burn care documentation and coding

Pabau helps clinical teams capture TBSA percentages, burn depth, and anatomical sites at the point of care – so the right ICD-10 codes are supported before the claim ever leaves the building.

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Conclusion

T31.52 only works as a code when the medical record proves two separate numbers. The total burn area must fall in the 50-59% TBSA range, and the third-degree share must fall in the 20-29% range.

A coder who has only one figure has to chase the missing detail. That delay slows the claim and raises denial risk at a severity level that already carries the highest stakes.

Burn units that require separate fields for total TBSA and third-degree extent fix this at the source. The fourth character then reflects what’s actually documented, instead of defaulting to the lowest option when data goes missing. That single change removes the most common error in this code family before a coder ever opens the chart.

Pabau’s digital forms and clinical records tools help burn care teams capture TBSA percentage, burn depth, and anatomical site at the point of care. That means the documentation already supports T31.52 by the time a coder reviews the chart. Book a demo to see how Pabau fits into your burn unit’s documentation workflow.

Continue your research

Need a code near the top of the TBSA range? ICD-10 Code T31.85 covers burns involving 80-89% body surface area and how that severity level is documented and sequenced.

Need a tool for estimating TBSA at the point of care? Body burn percentage chart walks through Rule of Nines estimation for adult burn patients.

Billing for the procedures that follow a burn diagnosis? CPT Code 11044 covers billing for bone debridement, a procedure that can accompany severe full-thickness burns.

Managing electrolyte replacement during burn resuscitation? HCPCS Code J0610 covers billing for calcium gluconate injections and its J0612 crosswalk.

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