Urology Coding Alert

Question: I am still confused by the Excludes1 and Excludes2 instructions in ICD-10. Can you clarify the difference between them?

Iowa Subscriber

Answer: Excludes1 and Excludes2 instructions sound like they are similar notes. In fact, they have completely different functions in diagnosis coding.

ICD-10 guideline A.12.a. explains that ICD-10 regards an Excludes1 note as a “pure exclusion note.” The note means you cannot code two conditions together because, medically, they cannot exist together and are generally mutually exclusive. To drive that point home, the guideline adds the words “NOT CODED HERE!” in capital letters and with an exclamation point.

So, consider the Excludes1 note found underneath a code such as N21.9 (Calculus of lower urinary tract, unspecified):

• calculus of urinary tract NOS (N20.9)

When both diagnoses are documented, you should exclusively report the code included in the Excludes1 parenthetical note, N20.9, as per American Hospital Association (AHA) Coding Clinic (Q4, 2018) guidelines.

Note this exception: You can code Excludes1 codes together “when the two conditions are unrelated to each other.” So, even though N20.9 is listed as an Excludes1 code for N21.9, if your provider documents that a patient has lower urinary tract calculus in addition to another unspecified calculus of urinary tract diagnosis, you would be correct in overriding the Excludes1 note and recording both conditions with the two codes.

An Excludes2 note, on the other hand, means a specific condition is “not included here.” In other words, a condition identified by an Excludes2 note is not part of the condition represented by the main code. It is separately reportable under circumstances when the patient has both conditions simultaneously.

As an example, code N21.1 (Calculus in urethra) has an Excludes2 note of “calculus of prostate (N42.0).” This means that when you’ve got documentation of both conditions, you may report both codes separately.

Coding alert 1: Never assume that Excludes notes are reciprocal. ICD-10 exclusions do not necessarily work both ways. For example, there is no corresponding note for code N20.9 that makes N21.9 an Excludes1 code for unspecified urinary calculus.

Coding alert 2: Be sure to look to the instructions under each level in a code group, such as the Excludes2 note example above, as well as the ones that may accompany the specific code itself to find all the Excludes notes that apply to a specific code. For instance, Excludes notes at the three-character level apply to all codes in that family, including any five-character codes in the family that have additional Excludes notes under them.