2020 ICD-10-CM codes are all comprised of 3, 4, 5, 6, or 7 characters. The first character is alphabetical, followed by the next two numeric characters; this first group of 3 characters represents the category, and this category group may be followed by a 4th, 5th, or 6th character for higher specificity.
The 7th character represents the type of encounter, or phase of treatment; this could be an initial encounter, a subsequent encounter, or a sequela (previously known as a late effect). The conditions found in Chapter 19 of the codebook are Injury, Poisoning, and Certain Other Consequences of External Causes (S00-T88) and most of these require the 7th character to identify the type of encounter. Fracture care is an exception, and this will be addressed below, but first I want to describe the challenges coders face when trying to determine initial vs. subsequent vs. sequela.
Initial encounters are described as active treatment (use letter “A” when assigning initial care codes); if the patient presents to the emergency department for a lacerated finger, the first listed code will end in the letter A to describe the initial active treatment by the ED provider; if the patient then sees her Primary Care Physician (PCP) the next day, the first listed code will again end in the letter A because the injury is still undergoing active treatment and it will be the first encounter with that new provider (the PCP). Now say the patient requires complex surgery and is referred to a surgeon specialist, that surgery encounter will once again have the letter A as the 7th character because the laceration is still undergoing active treatment and the surgeon is a newest provider on the “team” to treat the same injury.
Subsequent encounters are described as the recovery phase (use letter “D” when assigning subsequent care codes). Using the same scenario above, after the surgery, the patient may see the PCP again to ensure proper healing. This time the first listed code will end in the letter D to depict the healing phase of the injury. The tricky issue to remember when assigning subsequent care codes is that the D is assigned when the patient is following the routine treatment plan set up during the initial encounter for the active treatment. But if the patient has an exacerbation of the injury, the encounter adjusts back to active treatment again and the 7th character will be the letter A until the patient reaches the routine healing phase again.
Sequela encounters are not driven by time (use letter “S” when assigning sequela codes); it may be 6 months (or less) or 6 years (or more) after the initial injury. So, using the same scenario as before, let’s say the patient is experiencing a painful knotting at the scar 3 years after ending treatment. The PCP diagnoses a keloid, which is a late effect from the previous laceration surgery. This time, the first listed code will have an S as the 7th character to reflect the late effect of the injury. ICD-10 defines sequela as “the residual effect (condition produced) after the acute phase of an illness or injury has terminated.”
When coding for fracture care, the 7th character choices are expanded to include the following:
A - initial encounter for closed fracture
B - initial encounter for open fracture
D - subsequent encounter for fracture with routine healing
G - subsequent encounter for fracture with delayed healing
K - subsequent encounter for fracture with nonunion
S - sequela
The key is to always code to the highest specificity, and when dealing with the conditions found in Chapter 19, review the chapter-specific guidelines and look for the coding key which is found within each category of the chapter, paying special attention to the coding key found in the fracture categories!
