Q42 ICD-10-CM Code: Congenital absence, atresia and stenosis of large intestine

Q42 is the ICD-10-CM diagnosis code for congenital absence, atresia and stenosis of large intestine. Q42 sits in the ICD-10-CM chapter for congenital malformations, deformations and chromosomal abnormalities (q00-qa0), within the section covering other congenital malformations of the digestive system (q38-q45).

Header codes like Q42 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at Q42's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.