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ICD-10-CM 2027

ICD-10 code for anus impervious

Q42.3

Congenital absence, atresia and stenosis of anus without fistula

✓ Billable / specificCC — complication/comorbidity

From the official ICD-10-CM alphabetic index entry “Impervious (congenital) › anus”. Page updated September 29, 2026.

About coding anus impervious

The ICD-10-CM code for anus impervious is Q42.3 (Congenital absence, atresia and stenosis of anus without fistula). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on Q42.3.

Within Q42, choose Q42.3 (anus without fistula) only when documentation doesn't support a more specific option: rectum with fistula (Q42.0), rectum without fistula (Q42.1), anus with fistula (Q42.2), other parts of large intestine (Q42.8) and part unspecified (Q42.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

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 anus impervious codes (official index)

  • with fistula Q42.2 — Congenital absence, atresia and stenosis of anus with fistula

Common questions about anus impervious ICD-10 codes

What is the ICD-10 code for anus impervious?

Q42.3 — Congenital absence, atresia and stenosis of anus without fistula. More specific codes apply when the documentation supports them: Q42.2.

Is Q42.3 billable?

Yes. Q42.3 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Q42.3 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Q42.3 as a principal diagnosis.

Is Q42.3 a CC or MCC?

Q42.3 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.