ICD-9-CM diagnosis code (retired)
721.6 — Ankylosing vertebral hyperostosis
ICD-9-CM was replaced by ICD-10 on October 1, 2015. These are the ICD-10-CM equivalents from the CMS General Equivalence Mappings.
About ICD-9-CM 721.6
721.6 is an ICD-9-CM diagnosis code for ankylosing vertebral hyperostosis. ICD-9-CM was retired for U.S. claims on October 1, 2015, when ICD-10-CM took over.
The CMS General Equivalence Mappings translate it to one ICD-10-CM code, M48.10 (Ankylosing hyperostosis [Forestier], site unspecified). The match is approximate, so confirm it against the record.
ICD-10-CM equivalents
- M48.10Ankylosing hyperostosis [Forestier], site unspecifiedapproximate
Common questions about 721.6
What is the ICD-10 code for ICD-9 721.6?
- The GEMs map 721.6 to ICD-10-CM M48.10.
GEMs are a translation aid, not a substitute for coding from the record. The 2027 ICD-10 code set has changed since the last GEMs release in 2018. Page updated September 29, 2026.