Eli's Rehab Report

Question: What do "NEC" and "NOS" mean in ICD-9 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 the book's fault. Your physiatrist 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 physiatrist'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.
  
An example of when you would use an NEC code: Your physician specifies spinal nerve root compression. You look in the 724.x category, Other and unspecified disorders of back, for the appropriate code. Codes 724.0-724.8 do not list the manifestation that the physician indicated, so you should report 724.9 (Other unspecified back disorders), which includes "compression of spinal nerve root NEC."
 
In contrast, suppose the physiatrist notes "vertebrogenic syndrome." The physician doesn't specify what the syndrome is, so you should report 724.5 (Backache, unspecified). This code includes "verte-brogenic (pain) syndrome NOS."