ICD-10-CM 2027
ICD-10 code for Chalasia
From the official ICD-10-CM alphabetic index entry “Chalasia (cardiac sphincter)”. Page updated September 29, 2026.
About coding Chalasia
The ICD-10-CM code for Chalasia is K21.9 (Gastro-esophageal reflux disease without esophagitis).
Within K21, choose K21.9 (without esophagitis) only when documentation doesn't support a more specific option: with esophagitis (K21.0).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Chalasia ICD-10 codes
What is the ICD-10 code for Chalasia?
- K21.9 — Gastro-esophageal reflux disease without esophagitis.
Is K21.9 billable?
- Yes. K21.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K21.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K21.9 as a principal diagnosis.
Is K21.9 a CC or MCC?
- No. K21.9 is neither a CC nor an MCC under MS-DRG v44.0.