ICD-10-CM 2027
ICD-10 code for alimentary tract anomaly
From the official ICD-10-CM alphabetic index entry “Anomaly, anomalous (congenital) (unspecified type) › alimentary tract”. Page updated September 29, 2026.
About coding alimentary tract anomaly
The ICD-10-CM code for alimentary tract anomaly is Q45.9 (Congenital malformation of digestive system, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on Q45.9.
Within Q45, choose Q45.9 (Congenital malformation of digestive system, unspecified) only when documentation doesn't support a more specific option: agenesis, aplasia and hypoplasia of pancreas (Q45.0), Annular pancreas (Q45.1), congenital pancreatic cyst (Q45.2), other congenital malformations of pancreas and pancreatic duct (Q45.3) and other specified congenital malformations of digestive system (Q45.8).
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 393 (Other Digestive System Diagnoses with MCC, relative weight 1.5881), DRG 394 (Other Digestive System Diagnoses with CC, relative weight 0.9228) and DRG 395 (Other Digestive System Diagnoses without CC/MCC, relative weight 0.6382), 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.
More specific alimentary tract anomaly codes (official index)
- upper Q40.9 — Congenital malformation of upper alimentary tract, unspecified
Common questions about alimentary tract anomaly ICD-10 codes
What is the ICD-10 code for alimentary tract anomaly?
- Q45.9 — Congenital malformation of digestive system, unspecified. More specific codes apply when the documentation supports them: Q40.9.
What is the ICD-10 code for upper alimentary tract anomaly?
- Q40.9 — Congenital malformation of upper alimentary tract, unspecified.
Is Q45.9 billable?
- Yes. Q45.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q45.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q45.9 as a principal diagnosis.
Is Q45.9 a CC or MCC?
- No. Q45.9 is neither a CC nor an MCC under MS-DRG v44.0.