Neurosurgery Coding Alert

Question: What do "NEC" and "NOS" mean in diagnosis coding? How should I choose between them?

Florida Subscriber

Answer: ICD-9 uses the abbreviations NEC and NOS to denote diagnoses "not elsewhere classified" and "not otherwise specified." NEC is equivalent to using an "other" code selection, and NOS is equivalent to using an "unspecified" code selection.

Think of NEC as a shortcoming in the ICD-9 manual: Your neurosurgeon provides specific findings, but ICD-9 does not list a specific code that describes the diagnosis.

On the other hand, consider NOS a documentation problem: The surgeon's documentation does not provide enough information to assign a more specific code.

For example, you may use an NEC code if your surgeon specifies "coccygeal abnormality". You look in the 724.x category, Other and unspecified disorders of back, for the appropriate code. Codes 724.7x Disorders of coccyx requires a fifth digit, but since the diagnosis is very general, you must use 724.70, Unspecified disorder of coccyx.

In contrast, suppose the surgeon documents "coccygodynia." The physician has specified the syndrome, so you should report 724.79 (Disorders of the coccyx; other). This code still includes a wide range of pain-causing conditions.