ICD-9-CM diagnosis code (retired)
255.12 — Conn's syndrome
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 255.12
255.12 is an ICD-9-CM diagnosis code for Conn's syndrome. 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, E26.01 (Conn's syndrome). The match is exact.
ICD-10-CM equivalents
- E26.01Conn's syndromeexact match
Common questions about 255.12
What is the ICD-10 code for ICD-9 255.12?
- The GEMs map 255.12 to ICD-10-CM E26.01.
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.