A74 ICD-10-CM Code: Other diseases caused by chlamydiae

A74 is the ICD-10-CM diagnosis code for other diseases caused by chlamydiae. A74 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering other diseases caused by chlamydiae (a70-a74).

Header codes like A74 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 A74'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.