Radiology Coding Alert

Use 2 examples to master Excludes1 vs. Excludes2.

Kidney stone sufferers number in the millions each year. Because those numbers are on the rise, the diagnosis code for this ailment is sure to still rank among your commonly used codes when the transition to ICD-10 occurs in 2013.

Good news: For "calculus of kidney and ureter" codes, you'll find almost a one-to-one code correspondence between ICD-9 2011 and ICD-10 2011:

As shown above, the major difference is that ICD-10 offers a code (N20.2) that is appropriate when the patient has calculi of both the kidney and the ureter. Under ICD-9, you would report the same diagnosis using two codes (592.0 and 592.1).

Instructional notes: The "includes" notes for these codes are nearly identical for ICD-9 and ICD-10. Be sure to take special care in reviewing the "excludes" notes, though, because ICD-10 has two different types of excludes notes that have two different meanings.

ICD-9 guidelines explain that an excludes note reveals terms that you should code elsewhere. "The term excludes means 'DO NOT CODE HERE,'" the guidelines state. For example, an ICD-9 excludes note instructs you to assign 275.49 for nephrocalcinosis rather than using a code in the 592 range (Calculus of kidney and ureter).

In contrast, ICD-10 has both "Excludes1" and "Excludes2" notes. According to ICD-10 guidelines, Excludes1 means "NOT CODED HERE." In fact, you should never report the excluded code "at the same time as the code above the Excludes 1 note," the guidelines state. Excludes1 means the "two conditions cannot occur together."

An Excludes2 note instead tells you that the excluded term should be reported using another code, but if the patient has both conditions you may report both codes. In other words, "When an Excludes2 note appears under a code it is acceptable to use both the code and the excluded code together," ICD-10 guidelines state.

Excludes1 example: ICD-10 lists an Excludes1 note directly under N20 (Calculus of kidney and ureter). That means the note applies to the entire N20 range. The excluded terms are "nephrocalcinosis" (E83.5-, Disorders of calcium metabolism) and "that with hydronephrosis" (N13.2, Hydronephrosis with renal and ureteral calculous obstruction).

Because these terms are listed as an Excludes1 note, you should never report N20.- with N13.2 or the code for nephrocalcinosis (E83.5).

Excludes2 example: Code N21.0 (Calculus in bladder) has an Excludes2 note for staghorn calculus indicating you should use N20.0 rather than N21.0 for that diagnosis. But because this is an Excludes2 note, if the documentation shows both "staghorncalculus" (N20.0) and "calculus in bladder" (N21.0), you may report the codes for each on the same claim.

Reminder: When ICD-10 goes into effect on Oct. 1, 2013, you should apply the codes and official guidelines in effect at that time (or more specifically, always use the codes and guidelines effective for the relevant date of service). Learn more at www.cms.gov/ICD10/ and www.cdc.gov/nchs/icd/icd10cm.htm#10update.