Question: What distinguishes "obesity" from "morbid obesity"? North Carolina Subscriber Answer: ICD-9 defines morbid obesity as "increased weight beyond limits of skeletal and physical requirements (125 percent or more over ideal body weight), as a result of excess fat in subcutaneous connective tissues." If the patient meets the definition of severe or morbid obesity, you should assign 278.01 (Morbid obesity). When patients do not meet the definition for morbid obesity, you should instead list 278.00 (Obesity, unspecified). Exception: When the patient's increased weight is due to a medical condition, such as adiposogenital dystrophy (253.8) or obesity of endocrine origin (259.9), you should report the underlying condition instead of morbid obesity (this would not normally be the case for patients undergoing gastric bypass). -- Reader Questions and You Be the Coder reviewed by Michael A. Granovsky, MD, CPC, FACEP, president of MRSI, an ED coding and billing company in Woburn, Mass.