Primary Care Coding Alert

There’s more to coding condition aftereffects that adding a seventh character.

Many injuries and illnesses don’t end after their acute phase is over. Some can have aftereffects that can last years or even a lifetime. From a coding perspective, that can present numerous problems. Knowing when to use the seventh character, S, to indicate sequela for an injury code from S00-T88 (Injury, Poisoning, and Certain Other Consequences of External Causes) or an external cause code from V00-Y99 (External Causes of Morbidity), for example, can be extremely tricky.

That’s why we put together this advice to help you choose the right seventh character or sequela code correctly and keep your ICD-10 coding on track.

Know the Definition of Sequela

ICD-10 guideline 1.B.10 describes sequela, or late effects, as the following: “A sequela is the residual effect (condition produced) after the acute phase of an illness or injury has terminated. There is no time limit on when a sequela code can be used. The residual may be apparent early, such as in cerebral infarction, or it may occur months or years later, such as that due to a previous injury.”

In other words, “the easiest way to define sequela is to say, ‘the previous illness or injury is completely resolved/ healed, but a new issue has developed due to the original illness/injury.’ So, a sequela code, or the seventh character, S, allows us to show the relationship,” explains Chelle Johnson, CPMA, CPC, CPCO, CPPM, CEMC, AAPC Fellow, billing/credentialing/auditing/coding coordinator at County of Stanislaus Health Services Agency in Modesto, California.

Know When an Aftereffect is Not a Sequela

Even though most medical conditions are the result of a cause-and-effect relationship, it is important to note that causality does not always mean sequela. Complications from a medical procedure, for example, are not regarded as sequela, and neither are symptoms of illnesses and conditions caused by organisms.

So, even though you would code a UTI caused by a staph infection with two codes, such as N39.0 (Urinary tract infection, site not specified) and B95.- (Streptococcus, Staphylococcus, and Enterococcus as the cause of diseases classified elsewhere), the UTI in this example is not regarded as a sequela of the infection but a result of it.

How Sequelae Are Coded

ICD-10 guidelines tell you to generally code sequelae “sequenced in the following order: the condition or nature of the sequela is sequenced first. The sequela code is sequenced second.”

Some sequelae have their own code or code group, such as:

• B94.- (Sequelae of other and unspecified infectious and parasitic diseases)
• I69.- (Sequelae of cerebrovascular disease)
• O94 (Sequelae of complication of pregnancy, childbirth, and the puerperium)

In these cases, you would use one of the specific sequela codes after the condition code, as in the following three examples:

Example 1: A female patient reports to your provider with a UTI. During the exam, the woman tells your provider that she had experienced a miscarriage several weeks earlier. Your provider diagnoses her with a UTI due to her retaining products of conception. In this case, the UTI is regarded as a sequela of the miscarriage, which means you would code O03.38 (Urinary tract infection following incomplete spontaneous abortion) followed by the sequela code O94.

Example 2: “Section 1.C.1.g.1.l of the ICD-10 guidelines also provides an example. It states, in part, that if MIS [Multisystem Inflammatory Syndrome] develops as a result of a previous COVID-19 infection, assign codes M35.81 [Multisystem inflammatory syndrome] and B94.8 [Sequelae of other specified infectious and parasitic diseases],” notes Kent Moore, senior strategist for physician payment at the American Academy of Family Physicians.

Example 3: “Patients who have suffered a stroke, might experience sequela such as memory deficit or speech or language deficits, which would be coded with I69.011 (Memory deficit following nontraumatic subarachnoid hemorrhage) and I69.02- (Speech and language deficits following nontraumatic subarachnoid hemorrhage) respectively,” Moore explains.

Know When 7^th Character S Comes Into Play

Sequelae that occur in relation to an injury or accident do not have their own codes. Instead, as ICD-10 guideline I.C.19.a notes, for certain codes in the S00-T88 and V00-Y99 sections, “the 7th character ‘S’, sequela, is for use for complications or conditions that arise as a direct result of a condition…. 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 … is sequenced first, followed by the injury code.”

“So, using the example to which the guidelines allude, if one were coding scar formation as a sequela to a burn, you would code the scar first and then the burn injury code second and add ‘S’ in the seventh position on the burn injury code only,” says Moore.

Example 4: A patient reports with a contracture — a condition where a joint becomes rigid or deformed due to a hardening or shortening of connective tissue, tendons, or muscles — of the left shoulder. During the history portion of the exam, your provider notes that the patient had fractured the scapular neck of the same shoulder many years earlier. In this case, the contracture would be considered a sequela of that fracture, and you would code the diagnosis as