ICD-9-CM diagnosis code (retired)
523.42 — Chronic periodontitis, generalized
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 523.42
523.42 is an ICD-9-CM diagnosis code for chronic periodontitis, generalized. 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 4 ICD-10-CM codes, such as K05.321 (Chronic periodontitis, generalized, slight), K05.322 (Chronic periodontitis, generalized, moderate) and K05.323 (Chronic periodontitis, generalized, severe). All of these are approximate matches, so review the record to pick the right one.
ICD-10-CM equivalents
Common questions about 523.42
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.