Coding for Burns

Coding for Burns

Approximately every minute, someone in the United States sustains a burn injury serious enough to require treatment. According to the American Burn Association, an estimated 486,000 hospital admissions and visits to hospital emergency departments occur annually for burn evaluation and treatment in the United States. The likelihood for a medical coder to have to code a burn case is extremely high. Here’s what you need to know.

Burn Types

A burn is tissue damage with partial or complete destruction of the skin caused by heat, chemicals, electricity, sunlight, or nuclear radiation. Proper selection of burn codes requires consideration of the location of the burn, severity, extent, and external cause in addition to laterality and encounter. ICD-10 makes a distinction between burns and corrosions:

  • Burn codes apply to thermal burns (except sunburns) that come from a heat source, such as fire, hot appliance, electricity, and radiation.
  • Corrosions are burns due to chemicals.

Degrees of Burns

Burn severity is classified based on the depth of the burn. There are six degrees of burns:

  • First-degree burns damage the outer layer (epidermis) of the skin; erythema
  • Second-degree burns indicate blistering with damage extending beyond the epidermis partially into the layer beneath it (dermis)
  • Third-degree burns indicate full-thickness tissue loss with damage or complete destruction of both layers of skin (including hair follicles, oil glands, & sweat glands)


ICD-10 Coding Using the “Rules of Nines”

TBSA Rule of ninesYou need at least three codes to properly report burn diagnoses:

First-listed code(s): S/S for site and severity (categories T20-T25)

  • Your first-listed code will be a combination code that reports both the site and severity of the injury. The descriptions of codes in the T20-T28 range are first defined by an anatomical location of the body affected by burn or corrosion.
  • The fourth character for each category identifies the severity (except categories T26-T28). Using the layers of the skin, the severity of a burn is identified by degree.
  • The fifth character reports additional details regarding the anatomical site of the burn.
  • The sixth character represents laterality.

Next listed code: E for extent (categories T31/32)

  • Burns and corrosions are classified according to the extent, or percentage, of the total body surface area involved (TBSA).
  • Code T31 to report a burn and T32 to report corrosion, based on the classic “rule of nines.”
    • The rule of nines, for adult patients, assigns 1% of TBSA to the genitalia, and multiples of 9% to other body areas (9% head, 9% per arm, 18% per leg, etc.).
    • A modified rule of nines is applied for infants, to account for their relatively larger head (18%) and smaller legs (14%, each).
  • The required fourth character identifies the percentage of the patient’s entire body affected by burns. The fifth character identifies the percentage of the patient’s body that is suffering from third-degree burns or corrosions only.

Lastly, code(s): E for external cause code(s)

  • External Cause – To identify the source, place, and intent of the burn.
  • Agent – To identify the chemical substance of the corrosion.

ICD-10-CM guidelines recommend reporting appropriate external cause codes for burn patients. Not all payers accept these codes, however.

CPT Coding Using the Lund-Browder Classification

CPT codes to report local treatment of burns and many skin grafting procedure codes, specify the surface area (TBSA) treated. CPT® utilizes the more precise Lund-Browder classification method to calculate TBSA for burns and grafts. Lund-Browder divides the body into 19 distinct areas and specifies six different age groups to account for the changes in body composition during development into adulthood.
The CPT® code book contains a Lund-Browder classification method chart for easy TBSA calculation by body area and patient age.
Lund-Browder Classification

Stacy Chaplain

About Has 72 Posts

Stacy Chaplain, MD, CPC, is a development editor at AAPC. She has worked in medicine for more than 20 years, with an emphasis on education, writing, and editing since 2015. Prior to AAPC, she led a compliance team as director of clinical coding quality for a multispecialty group practice. Chaplain received her Bachelor of Arts in biology from the University of Texas at Austin and her Medical Doctorate from the University of Texas Medical Branch in Galveston. She is a member of the Beaverton, Oregon, local chapter.

3 Responses to “Coding for Burns”

  1. Dawne Trouant says:

    Thank you! This was an extremely helpful article. I am testing this weekend, and this information is going to help trememdously! Sequencing is crucial, and the article breaks it out perfectly!

  2. Atul kumar says:

    fell asleep while smoking a cigarette, and woke up when he dropped a cigarette on his abdomen. Approximately 0.5 cm second-degree burn on the abdominal wall due to a cigarette burn. what are the codes we need to add. for this in coding. do we need to add T31 series as mandate code when burn is there if so then how we calculate burn percentage if this Is the complete documentation?

  3. Lee Fifield says:

    From the author: In this scenario, you would need to code for the second-degree burn to the abdomen (T21.22XA) and the external cause; a T31.- category code is optional. The guidelines state that it is advisable to use category T31 as additional coding when needed to provide data for evaluating burn mortality, such as that needed by burn units. It is also advisable to use category T31 as an additional code for reporting purposes when there is mention of a third-degree burn involving 20 percent or more of the body surface. Because this patient did not have third-degree burns and the burns affected less than 20 percent of the patient’s body, a code from the T31.- category isn’t necessary, but can be submitted for data collection purposes; you can code T31.0 Burns involving less than 10 percent of the body.