Hyposmolality and/or hyponatremia. 1  Short description: Hyposmolality. 2  ICD-9-CM 276.1 is a billable medical code that can be used to indicate a diagnosis on a reimbursement claim, however, 276.1 should only be used for claims with a date of service on or before September 30, 2015. 3  You are viewing the 2012 version of ICD-9-CM 276. 1.