O28 ICD-10-CM Code: Abnormal findings on antenatal screening of mother

O28 is the ICD-10-CM diagnosis code for abnormal findings on antenatal screening of mother. O28 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering other maternal disorders predominantly related to pregnancy (o20-o29).

Header codes like O28 cannot be reported on claims directly; they organize child codes that share clinical context. Coders should select the billable child code that matches the documented presentation and then verify its current source-backed HCC mapping. Do not infer a child code or risk adjustment value from the header alone.