ICD-10-CM 2027
ICD-10 code for respiratory system anomaly
From the official ICD-10-CM alphabetic index entry “Anomaly, anomalous (congenital) (unspecified type) › respiratory system”. Page updated September 29, 2026.
About coding respiratory system anomaly
The ICD-10-CM code for respiratory system anomaly is Q34.9 (Congenital malformation of respiratory 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 Q34.9.
Within Q34, choose Q34.9 (Congenital malformation of respiratory system, unspecified) only when documentation doesn't support a more specific option: anomaly of pleura (Q34.0), congenital cyst of mediastinum (Q34.1) and other specified congenital malformations of respiratory system (Q34.8).
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 205 (Other Respiratory System Diagnoses with MCC, relative weight 1.8244) and DRG 206 (Other Respiratory System Diagnoses without MCC, relative weight 0.9257), in MDC 04 (Diseases and Disorders of the Respiratory 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 respiratory system anomaly codes (official index)
- specified NEC Q34.8 — Other specified congenital malformations of respiratory system
Common questions about respiratory system anomaly ICD-10 codes
What is the ICD-10 code for respiratory system anomaly?
- Q34.9 — Congenital malformation of respiratory system, unspecified. More specific codes apply when the documentation supports them: Q34.8.
Is Q34.9 billable?
- Yes. Q34.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q34.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q34.9 as a principal diagnosis.
Is Q34.9 a CC or MCC?
- No. Q34.9 is neither a CC nor an MCC under MS-DRG v44.0.