Gastroenterology Coding Alert

Question: What do "NEC" and "NOS" mean in ICD-9 coding? How should I select between them?

Florida Subscriber

 Answer: ICD-9 uses the abbreviations NEC and NOS for "not elsewhere classified" and "not otherwise specified," respectively. Think of NEC as the book's fault. Your gastroenterologist provides specific findings, but the book does not list a specific code that describes the diagnosis. On the other hand, consider NOS your physician's fault. Your physician's documentation does not provide enough information to assign a more specific diagnosis code. NEC codes are frequently highlighted in gray in the ICD-9 manual, and NOS codes are usually highlighted in yellow.
 
For example, you would use an NEC code if the physician specifies prolapse as a complication arising with a colostomy or enterostomy. You should look in the 569 series of the ICD-9 codes, Other disorders of intestine, then the 569.6 subcategory, Colostomy and enterostomy complications, for the appropriate code. Codes 569.60-569.69 do not list the specific manifestation that the physician indicated. Because the doctor states a manifestation, you can't use 569.60 (Colostomy and enterostomy complication, unspecified). Consequently, the correct ICD-9 code is 569.69 (Other complication).
 
In contrast, suppose the gastroenterologist diagnoses ulcerative colitis but does not record a specific location. Even when you ask for additional detail, your gastroenterologist may not be able to provide you with an exact location. Without more information from your physician as to the location of the inflammation, you should report 556.9 (Ulcerative colitis, unspecified).