Oncology & Hematology Coding Alert

Diagnosis coding can take years to master, and part of the reason for that is because the ICD-10-CM code book has so many nuances. Chief among them is the Excludes1 parenthetical note, which is typically among the last of these concepts to “click” for beginning coders. That’s partly because, up until recently, there were no clear instructions on whether you should report the tabular code, or the code included in the parenthetical note.

“Coding Excludes1 notes has been a controversial topic among many hospitals and practices due to a lack of definitive guidelines,” says Lindsay Della Vella, COC, medical coding auditor at Precision Healthcare Management in Media, Pennsylvania. “But you should be aware of a more recent American Hospital Association (AHA) Coding Clinic (Q4, 2018) that provides some much-needed clarity on diagnoses paired by an Excludes1 note,” Della Vella explains.

Get a breakdown of the problem at hand and how you can address it with Coding Clinic guidance.

Recall Appropriate Settings, Context for Exludes1 Notes

Refresher: The ICD-10-CM guidelines offer the following instructions regarding an Excludes1 note:

“A type 1 Excludes note is a pure excludes note. It means ‘not coded here.’ An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.”

As you can see, these guidelines simply instruct you not to code any two given diagnoses at the same time. The classic conundrum that coders experience time and time again comes in their confusion about which code should they report versus which they should omit. Fortunately, the AHA Coding Clinic offers a definitive answer in their 2018 Q4 edition.

Rely on Coding Clinic Q&A to Settle the Debate

In the Coding Clinic Q&A, the reader asks for guidance in determining whether the main code listed in the tabular or the code referenced in the Excludes1 note should be reported. The Coding Clinic responds as follows:

“Assign only the code referenced in the Excludes1 note.”

This means that, assuming one of the two diagnosis codes has an Excludes1 note beneath it, you should code according to the Excludes1 note instructions. Consider a scenario where the provider documents a patient with calculus of the kidney and nephrocalcinosis under the following ICD-10-CM codes:

• N20.0 (Calculus of kidney)
• E83.59 (Other disorders of calcium metabolism)

Since there are no diagnosis-relevant Excludes1 notes listed under code E83.59 or category code E83 (Disorders of mineral metabolism), you will next look at the Excludes1 notes for N20.- (Calculus of kidney and ureter). Here you can see, among other Excludes1 notes, that the following note is listed: “nephrocalcinosis (E83.5-)”

Based on the Coding Clinic guidelines, you should report the code listed in the N20.- Excludes1 note, specifically E83.53. However, consider a scenario in which both diagnosis codes offer an Excludes1 note advising to use the other respective diagnosis code. Unfortunately, the Coding Clinic still does not offer guidance on how you should address this particular scenario.

However, inferring from the above guidelines, the Coding Clinic would presumably allow for the coder to choose between either coding option. Ideally, if one diagnosis code is distinctively primary over another, you should report the primary coding option and disregard the secondary. “Until the AHA offers further advice on the subject, coders should consider the Coding Clinic guidance when reviewing paired Excludes1 notes, but ultimately use their own judgment on which code best supports the documented diagnosis,” advises Sheri Poe Bernard, CPC, of Poe Bernard Consulting in Salt Lake City, Utah.

Remember: There may be some confounding circumstances in which you code both the tabular code and the code referenced in the Excludes1 note. When two conditions are clinically unrelated to one another, ICD-10-CM guidelines allow you to disregard the Excludes1 note and report both diagnoses separately. Query the provider if it is not clear whether a relation between the two diagnoses exists.

Know When Not to Adhere to Excludes1 Guidelines

In the same quarterly issue, Coding Clinic addresses one final situation involving the use of anExcludes1 parenthetical notation. In this reader question, the reader questions the coding of nutritional anemia along with unspecified anemia. In this example, D53.9 (Nutritional anemia, unspecified) has an Excludes1 note instructing the coder to code D64.9 (Anemia, unspecified) when the provider also documents “anemia NOS.”

The Coding Clinic advises that, in this example, it would be inappropriate to follow by the Excludes1 guidelines and report only D64.9. That’s because, as the Coding Clinic puts it, “it would be contradictory to have a code for unspecified and another specified code for the same condition.” Even though this kind of example might be rare, it’s important to keep your thinking cap on when addressing diagnosis codes that involve Excludes1 notes. While this Excludes1 note appears to be an error on the part of the ICD-10-CM, the 2020, nor the upcoming 2021 code books address the issue.

However, it offers a valuable lesson that the general principles of coding should always be followed over parenthetical notes such as an Excludes1 note. In this case, do not code the same condition twice, even if ICD-10 instructs you to do so in the parenthetical notes.