Primary Care 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 family physician (FP) provides specific findings, but the book does not list a specific code that describes the diagnosis. On the other hand, consider NOS the equivalent of your doctor's fault: Your FP's documentation does not provide enough information to assign a more specific diagnosis code. NEC codes are highlighted in gray in the ICD-9 manual, and NOS codes are highlighted in yellow.

For example, you would use an NEC code if the physician specifies diabetic hypertension. You should look in the 250 category, diabetes mellitus, for the appropriate code. Codes 250.0-250.7 do not list the manifestation that the physician indicated. Because the doctor states a manifestation, you can't use 250.9x (Diabetes with unspecified complication). Consequently, the correct ICD-9 code is 250.80 (Diabetes with other specified manifestations).

In contrast, suppose the FP notes diabetes, complicated. The physician didn't specify what the complication was, so you should report 250.90.