Pediatric Coding Alert

Question: I’m still getting the hang of using the ICD-10 coding system, but I had a couple of questions that have been plaguing me. What is the purpose of the seventh character, and why is the letter “X” in certain codes?

Codify Subscriber

Answer: ICD-10 uses the seventh-character extensions to provide additional information about the characteristic of the encounter for episode of care for obstetrics, injuries and external causes of injuries. Consider the seventh character in these three ICD-10 codes:

• S43.422A, Sprain of left rotator cuff capsule, initial encounter
• S43.422D, Sprain of left rotator cuff capsule, subsequent encounter
• S43.422S, Sprain of left rotator cuff capsule, sequela.

For this diagnosis, the seventh character indicates if the patient is still having active treatment for the sprain, if the patient is in the healing phase of the sprain and having routine care, or if the patient has a complication as a result of the rotator cuff sprain. 

If the seventh character is there in the ICD-10 book for a diagnosis code, you must include one. For example, S43.422 would be considered a truncated or non-valid ICD-10 code. One of the three seventh characters for the S43 category must be reported.

X factor: ICD-10 uses the X placeholder when a code that requires a seventh character is not six characters in length; in these cases, you must use X to fill in the empty characters, Hammer explained.

For example, consider these ICD-10 codes containing X:

• S33.6XXA, Sprain of sacroiliac joint, initial encounter
• W14.XXXS, Fall from tree, sequela.

Remember, if ICD-10 uses a placeholder X, you must include the X in the code or ICD-10 will not consider it valid.