New Diagnoses Codes Leave Gastroenterologists Unaffected Gastroenterologists don't need to spend much time learning new diagnoses codes for 2003. The new ICD-9 codes, which include nearly 150 new diagnosis codes, as well as 19 code deletions, go into effect on Oct. 1, 2002. Payers must accept them by Jan. 1, 2003. Many of the new codes pertain to obstetrics and pediatrics. In addition, several new codes for terrorism and biological warfare have been created. For a complete list of ICD-9 changes and revisions, visit www.cms.hhs.gov/medlearn/icd9code.asp.