Chapter 19: Injury, poisoning, and certain other consequences of external causes (S00-T88)

a. Application of 7th Characters in Chapter 19

Most categories in chapter 19 have a 7th character requirement for each applicable code. Most categories in this chapter have three 7th character values (with the exception of fractures): A, initial encounter, D, subsequent encounter and S, sequela. Categories for traumatic fractures have additional 7th character values. While the patient may be seen by a new or different provider over the course of treatment for an injury, assignment of the 7th character is based on whether the patient is undergoing active treatment and not whether the provider is seeing the patient for the first time. For complication codes, active treatment refers to treatment for the condition described by the code, even though it may be related to an earlier precipitating problem. For example, code T84.50XA, Infection and inflammatory reaction due to unspecified internal joint prosthesis, initial encounter, is used when active treatment is provided for the infection, even though the condition relates to the prosthetic device, implant or graft that was placed at a previous encounter. 7th character "A", initial encounter is used for each encounter where the patient is receiving active treatment for the condition. 7th character "D" subsequent encounter is used for encounters after the patient has completed active treatment of the condition and is receiving routine care for the condition during the healing or recovery phase. The aftercare Z codes should not be used for aftercare for conditions such as injuries or poisonings, where 7th characters are provided to identify subsequent care. For example, for aftercare of an injury, assign the acute injury code with the 7th character "D" (subsequent encounter). 7th character "S", sequela, is for use for complications or conditions that arise as a direct result of a condition, such as scar formation after a burn. The scars are sequelae of the burn. When using 7th character "S", it is necessary to use both the injury code that precipitated the sequela and the code for the sequela itself. The "S" is added only to the injury code, not the sequela code. The 7th character "S" identifies the injury responsible for the sequela. The specific type of sequela (e.g. scar) is sequenced first, followed by the injury code. See Section I.B.10 Sequelae, (Late Effects)

b. Coding of Injuries

When coding injuries, assign separate codes for each injury unless a combination code is provided, in which case the combination code is assigned. Code T07, Unspecified multiple injuries should not be assigned in the inpatient setting unless information for a more specific code is not available. Traumatic injury codes (S00-T14.9) are not to be used for normal, healing surgical wounds or to identify complications of surgical wounds. The code for the most serious injury, as determined by the provider and the focus of treatment, is sequenced first.

1) Superficial injuries

Superficial injuries such as abrasions or contusions are not coded when associated with more severe injuries of the same site.

2) Primary injury with damage to nerves/blood vessels

When a primary injury results in minor damage to peripheral nerves or blood vessels, the primary injury is sequenced first with additional code(s) for injuries to nerves and spinal cord (such as category S04), and/or injury to blood vessels (such as category S15). When the primary injury is to the blood vessels or nerves, that injury should be sequenced first.

c. Coding of Traumatic Fractures

The principles of multiple coding of injuries should be followed in coding fractures. Fractures of specified sites are coded individually by site in accordance with both the provisions within categories S02, S12, S22, S32, S42, S49, S52, S59, S62, S72, S79, S82, S89, S92 and the level of detail furnished by medical record content. A fracture not indicated as open or closed should be coded to closed. A fracture not indicated whether displaced or not displaced should be coded to displaced. More specific guidelines are as follows:

1) Initial vs. Subsequent Encounter for Fractures

Traumatic fractures are coded using the appropriate 7th character for initial encounter (A, B, C) for each encounter where the patient is receiving active treatment for the fracture. The appropriate 7th character for initial encounter should also be assigned for a patient who delayed seeking treatment for the fracture or nonunion. Fractures are coded using the appropriate 7th character for subsequent care for encounters after the patient has completed active treatment of the fracture and is receiving routine care for the fracture during the healing or recovery phase. Care for complications of surgical treatment for fracture repairs during the healing or recovery phase should be coded with the appropriate complication codes. Care of complications of fractures, such as malunion and nonunion, should be reported with the appropriate 7th character for subsequent care with nonunion (K, M, N,) or subsequent care with malunion (P, Q, R). Malunion/nonunion: The appropriate 7th character for initial encounter should also be assigned for a patient who delayed seeking treatment for the fracture or nonunion. The open fracture designations in the assignment of the 7th character for fractures of the forearm, femur and lower leg, including ankle are based on the Gustilo open fracture classification. When the Gustilo classification type is not specified for an open fracture, the 7th character for open fracture type I or II should be assigned (B, E, H, M, Q). A code from category M80, not a traumatic fracture code, should be used for any patient with known osteoporosis who suffers a fracture, even if the patient had a minor fall or trauma, if that fall or trauma would not usually break a normal, healthy bone. See Section I.C.13. Osteoporosis. The aftercare Z codes should not be used for aftercare for traumatic fractures. For aftercare of a traumatic fracture, assign the acute fracture code with the appropriate 7th character.

2) Multiple fractures sequencing

Multiple fractures are sequenced in accordance with the severity of the fracture.

d. Coding of Burns and Corrosions

The ICD-10-CM makes a distinction between burns and corrosions. The burn codes are for thermal burns, except sunburns, that come from a heat source, such as a fire or hot appliance. The burn codes are also for burns resulting from electricity and radiation. Corrosions are burns due to chemicals. The guidelines are the same for burns and corrosions. Current burns (T20-T25) are classified by depth, extent and by agent (X code). Burns are classified by depth as first degree (erythema), second degree (blistering), and third degree (full-thickness involvement). Burns of the eye and internal organs (T26-T28) are classified by site, but not by degree.

1) Sequencing of burn and related condition codes

Sequence first the code that reflects the highest degree of burn when more than one burn is present.

2) Burns of the same local site

Classify burns of the same local site (three-character category level, T20-T28) but of different degrees to the subcategory identifying the highest degree recorded in the diagnosis.

3) Non-healing burns

Non-healing burns are coded as acute burns.

4) Infected Burn

For any documented infected burn site, use an additional code for the infection.

5) Assign separate codes for each burn site

When coding burns, assign separate codes for each burn site. Category T30, Burn and corrosion, body region unspecified is extremely vague and should rarely be used.

6) Burns and Corrosions Classified According to Extent of Body Surface Involved

Assign codes from category T31, Burns classified according to extent of body surface involved, or T32, Corrosions classified according to extent of body surface involved, when the site of the burn is not specified or when there is a need for additional data. 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. Categories T31 and T32 are based on the classic "rule of nines" in estimating body surface involved: head and neck are assigned nine percent, each arm nine percent, each leg 18 percent, the anterior trunk 18 percent, posterior trunk 18 percent, and genitalia one percent. Providers may change these percentage assignments where necessary to accommodate infants and children who have proportionately larger heads than adults, and patients who have large buttocks, thighs, or abdomen that involve burns.

7) Encounters for treatment of sequela of burns

Encounters for the treatment of the late effects of burns or corrosions (i.e., scars or joint contractures) should be coded with a burn or corrosion code with the 7th character "S" for sequela.

8) Sequelae with a late effect code and current burn

When appropriate, both a code for a current burn or corrosion with 7th character "A" or "D" and a burn or corrosion code with 7th character "S" may be assigned on the same record (when both a current burn and sequelae of an old burn exist). Burns and corrosions do not heal at the same rate and a current healing wound may still exist with sequela of a healed burn or corrosion. See Section I.B.10 Sequela (Late Effects)

9) Use of an external cause code with burns and corrosions

An external cause code should be used with burns and corrosions to identify the source and intent of the burn, as well as the place where it occurred.

e. Adverse Effects, Poisoning, Underdosing and Toxic Effects

Codes in categories T36-T65 are combination codes that include the substance that was taken as well as the intent. No additional external cause code is required for poisonings, toxic effects, adverse effects and underdosing codes.

1) Do not code directly from the Table of Drugs

Do not code directly from the Table of Drugs and Chemicals. Always refer back to the Tabular List.

2) Use as many codes as necessary to describe

Use as many codes as necessary to describe completely all drugs, medicinal or biological substances.

3) If the same code would describe the causative agent

If the same code would describe the causative agent for more than one adverse reaction, poisoning, toxic effect or underdosing, assign the code only once.

4) If two or more drugs, medicinal or biological substances

If two or more drugs, medicinal or biological substances are reported, code each individually unless a combination code is listed in the Table of Drugs and Chemicals.

(a) Adverse Effect

When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug (T36-T50). The code for the drug should have a 5th or 6th character "5" (for example T36.0X5-) Examples of the nature of an adverse effect are tachycardia, delirium, gastrointestinal hemorrhaging, vomiting, hypokalemia, hepatitis, renal failure, or respiratory failure.

(b) Poisoning

When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined. If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings. If there is also a diagnosis of abuse or dependence of the substance, the abuse or dependence is assigned as an additional code. Examples of poisoning include:

See Section I.C.4. if poisoning is the result of insulin pump malfunctions.

(c) Underdosing

Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. For underdosing, assign the code from categories T36-T50 (fifth or sixth character "6"). Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded. Noncompliance (Z91.12-, Z91.13-) or complication of care (Y63.6-Y63.9) codes are to be used with an underdosing code to indicate intent, if known.

(d) Toxic Effects

When a harmful substance is ingested or comes in contact with a person, this is classified as a toxic effect. The toxic effect codes are in categories T51-T65. Toxic effect codes have an associated intent: accidental, intentional self-harm, assault and undetermined.

f. Adult and child abuse, neglect and other maltreatment

Sequence first the appropriate code from categories T74.- (Adult and child abuse, neglect and other maltreatment, confirmed) or T76.- (Adult and child abuse, neglect and other maltreatment, suspected) for abuse, neglect and other maltreatment, followed by any accompanying mental health or injury code(s). If the documentation in the medical record states abuse or neglect it is coded as confirmed (T74.-). It is coded as suspected if it is documented as suspected (T76.-). For cases of confirmed abuse or neglect an external cause code from the assault section (X92-Y09) should be added to identify the cause of any physical injuries. A perpetrator code (Y07) should be added when the perpetrator of the abuse is known. For suspected cases of abuse or neglect, do not report external cause or perpetrator code. If a suspected case of abuse, neglect or mistreatment is ruled out during an encounter code Z04.71, Encounter for examination and observation following alleged physical adult abuse, ruled out, or code Z04.72, Encounter for examination and observation following alleged child physical abuse, ruled out, should be used, not a code from T76. If a suspected case of alleged rape or sexual abuse is ruled out during an encounter code Z04.41, Encounter for examination and observation following alleged adult rape or code Z04.42, Encounter for examination and observation following alleged child rape, should be used, not a code from T76. See Section I.C.15. Abuse in a pregnant patient.

g. Complications of care

1) General guidelines for complications of care

(a) Documentation of complications of care See Section I.B.16. for information on documentation of complications of care.

2) Pain due to medical devices

Pain associated with devices, implants or grafts left in a surgical site (for example painful hip prosthesis) is assigned to the appropriate code(s) found in Chapter 19, Injury, poisoning, and certain other consequences of external causes. Specific codes for pain due to medical devices are found in the T code section of the ICD-10-CM. Use additional code(s) from category G89 to identify acute or chronic pain due to presence of the device, implant or graft (G89.18 or G89.28).

3) Transplant complications

(a) Transplant complications other than kidney

Codes under category T86, Complications of transplanted organs and tissues, are for use for both complications and rejection of transplanted organs. A transplant complication code is only assigned if the complication affects the function of the transplanted organ. Two codes are required to fully describe a transplant complication: the appropriate code from category T86 and a secondary code that identifies the complication. Pre-existing conditions or conditions that develop after the transplant are not coded as complications unless they affect the function of the transplanted organs. See I.C.21. for transplant organ removal status See I.C.2. for malignant neoplasm associated with transplanted organ.

(b) Kidney transplant complications

Patients who have undergone kidney transplant may still have some form of chronic kidney disease (CKD) because the kidney transplant may not fully restore kidney function. Code T86.1- should be assigned for documented complications of a kidney transplant, such as transplant failure or rejection or other transplant complication. Code T86.1- should not be assigned for post kidney transplant patients who have chronic kidney (CKD) unless a transplant complication such as transplant failure or rejection is documented. If the documentation is unclear as to whether the patient has a complication of the transplant, query the provider. Conditions that affect the function of the transplanted kidney, other than CKD, should be assigned a code from subcategory T86.1, Complications of transplanted organ, Kidney, and a secondary code that identifies the complication. For patients with CKD following a kidney transplant, but who do not have a complication such as failure or rejection, see section I.C.14. Chronic kidney disease and kidney transplant status.

4) Complication codes that include the external cause

As with certain other T codes, some of the complications of care codes have the external cause included in the code. The code includes the nature of the complication as well as the type of procedure that caused the complication. No external cause code indicating the type of procedure is necessary for these codes.

5) Complications of care codes within the body system chapters

Intraoperative and postprocedural complication codes are found within the body system chapters with codes specific to the organs and structures of that body system. These codes should be sequenced first, followed by a code(s) for the specific complication, if applicable.