ICD-10-based expanded code set for use in cleft lip/palate research and surveillance.

BACKGROUND On October 1, 2015, the United States required use of the Clinical Modification of the International Classification of Diseases, 10th Revision (ICD-10-CM) for diagnostic coding. The ICD-10-CM code set is limited to gross categories for cleft lip and/or cleft palate (using only four of a possible seven characters). METHODS Herein, a clinically useful expansion of the ICD-10-CM code set is proposed to improve the diagnostic accuracy necessary for individual clinical, research, and statistical projects that require it. (This is similar to how the Centers for Disease Control and Prevention/British Paediatric Association Code served to extend the ICD-9 code base.) RESULTS: Our proposed expansion does not replace the required use of ICD-10-CM for clinical, administrative, or financial transactions. Rather, it is offered as an optional set of cleft codes that could be used in parallel to document true classification-level data with phenotypic accuracy. CONCLUSION The expanded set is "collapsible" into the official ICD-10-CM codes; this improves compatibility of the expanded codes that would be contained in research and epidemiologic databases with the standard codes from hospital electronic medical record systems and administrative billing data. Birth Defects Research (Part A) 106:905-914, 2016. © 2016 Wiley Periodicals, Inc.