Sequelae in ICD-10: What Coders Don't Want to Miss

A common question asked among medical coders is, “is this a complication or is this a sequela”?  Following specific coding guidelines will ensure the avoidance of costly errors that commonly occur for these two very different, but similarly named, coding situations.

A sequela in ICD-10 (formerly known as “late effects”) is a residual or produced condition that is a direct result of a past illness or injury. This condition may be apparent in the early stages following an acute phase of an illness, or the condition may appear later. However, it is important to note that with a sequela, the acute phase of an illness or injury has resolved or healed, and the sequela is left. Conversely, a complication is a condition that occurs as a result of treatment, or a condition that interrupts the healing process from an acute illness or injury. The acute illness or injury is not healed in a scenario involving a complication. Essentially, the difference comes down to the cause of the following condition, whether it was directly tied to the initial problem or simply coexisting alongside it.

Sequelae vs. Subsequent Conditions

Under ICD-10 medical coding guidelines, a sequela refers to a condition that results from a previous illness or injury and appears after the acute phase has resolved. In contrast, a subsequent condition denotes ongoing care during the recovery phase of the initial condition. This is represented by a seventh character “D” and indicates follow-up treatment and routine care during the healing process. Essentially, sequelae reflect long-term effects after healing, while subsequent conditions represent the ongoing treatment of the initial illness or injury.

Codes Required for Sequela in ICD-10

Most of the time when you’re coding a sequela, you’ll need to use two codes. One of those two codes will describe the nature of the sequela (that is, the residual effect or what you’re seeing right now) and one will describe the now-healed illness or injury that led to the current condition. Coding guidelines stipulate that the residual should be coded first, followed by the healed illness/injury.
For example, if a patient develops a right elbow contracture after a third- degree burn in the same area heals, the contracture is the residual effect and would be coded first with M24.521 (Contracture, right elbow) and immediately followed by T22.321S (Burn of third degree of right elbow, sequela). The seventh character “S” indicates that the burn is no longer an active condition, but rather that it healed and left behind a sequela, according to coding guidelines.

Sequela Example: Epilepsy Due to Traumatic Brain Injury (TBI)

A 65-year-old woman was a passenger in a car accident five years ago and suffered a TBI. As a result of the TBI, she has recurrent seizures and is admitted to home health for instruction on new medications to help control the seizures.

Primary and Secondary Diagnoses

Rationale: 

• Recurrent seizures are sequenced first, as they describe the nature of the sequela.
• A seventh character “S” on the TBI code is used to indicate that the TBI healed but left behind a sequela.
• The appropriate external cause code should be coded using a 7th character of “S” indicating the cause of the accident.
• Even though this accident was 5 years ago, there is no time limit on when sequelae codes can be used.

To read more on Sequelae, you can look for our article in the September edition of Decision Health. To view additional scenarios, see the online version of this story on the Home Health Coding Center at www.HHCodingCenter.com.

About the Contributor

Sheri Ikner, RN, BSN, COS-C, HCS-D

Sheri is a Clinical Manager for OASIS and Coding Services at McBee, a part of the Netsmart family. She holds the HCS-D and COS-C certifications and has been performing OASIS and coding reviews for 10 years.

Sequelae Frequently Asked Questions

What is a Sequela in ICD-10?

A sequela, formerly known as “late effects,” is a condition that results from a past illness or injury. It can become apparent in the early stages following an acute phase of an illness or may appear later.

How is a Sequela Different from a Complication?

A sequela is a residual condition after the acute phase of an illness or injury has resolved or healed. In contrast, a complication is a condition that arises as a result of treatment or interrupts the healing process of an acute illness or injury.

How is a Sequela Different from a Subsequent Condition?

Coding for a sequela involves two codes: one for the current residual condition and another for the original illness or injury. On the other hand, a subsequent condition refers to the continued treatment phase of the initial illness or injury, marked by the seventh character “D” in ICD-10. This indicates ongoing care and follow-up during the healing process. Essentially, sequelae are the long-term effects seen after recovery, while subsequent conditions are about continued treatment of the initial health issue.

How Many Codes are Typically Required for Sequela?

Usually, two codes are required when coding a sequela. One code describes the nature of the sequela (the residual condition), and the other describes the now-healed illness or injury that led to the sequela.

In What Order Should Sequela Codes be Used?

Coding guidelines stipulate that the residual condition should be coded first, followed by the code for the healed illness or injury.

Is There a Time Limit on When Sequelae Codes Can Be Used?

No, there is no time limit on when sequelae codes can be used. They can be applied regardless of how long ago the original illness or injury occurred.

What is the Importance of Accurate Sequela Coding?

Accurate sequela coding is crucial to avoid costly errors and to correctly represent the patient’s health condition for treatment and billing purposes.

Can You Provide an Example of How to Code a Sequela?

For instance, a patient with a right elbow contracture following a healed third-degree burn would be coded first with M24.521 (Contracture, right elbow) and then T22.321S (Burn of third degree of right elbow, sequela).

Can Sequela Occur in Both Early and Later Stages After an Illness or Injury?

Yes, a sequela can become apparent both in the early stages following the acute phase of an illness or injury and also appear later on. The key aspect of a sequela is that it occurs after the acute phase of the illness or injury has resolved or healed.

What are Examples of Sequela in Medical Terms?

Examples of sequelae include joint contracture following a tendon injury, hemiplegia after a stroke, or scar formation after a burn. These are conditions that manifest after the acute phase of an injury or illness has passed.

How is Sequela Different from a Subsequent Encounter in Medical Coding?

A sequela is used to describe a condition resulting from a previous event. A subsequent encounter, denoted by the seventh character “D” in ICD-10 coding, refers to routine care during the healing or recovery phase of an initial condition.

Can Sequelae Include Mental Health Issues?

Yes, sequelae can manifest in various ways, including physical impairment, cognitive impairment, mental health issues, or chronic pain.

How Do Sequelae Affect Medical Billing?

When a patient is admitted for sequelae, subsequent encounter codes are used for billing purposes. If the patient is readmitted later, the billing process may start with an initial code but switch back to subsequent codes as it relates to the previous condition.

When is a Sequela Code Appropriate?

A sequela code is appropriate only after the acute phase of the injury or illness has passed. It cannot be reported for the acute illness and a late effect at the same encounter for the same patient, except if both conditions exist simultaneously

What Does 'Sequelae' Mean in the Context of Chronic Conditions?

Sequelae in the context of chronic conditions refer to a range of conditions or complications that are a direct result of an initial acute illness or injury. These can include long-term impairments or disabilities stemming from the original condition.

Is There a Specific Time Frame for Coding Sequelae in Medical Billing?

In medical billing, there is no specific time frame for using sequelae codes. They can be applied at any point after the acute phase of the original illness or injury has passed, regardless of how much time has elapsed since the initial event.