Q86.8
BillableOther congenital malformation syndromes due to known exogenous causes
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q86.8 an HCC code?
No. Q86.8 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Q86.8 is the ICD-10-CM diagnosis code for other congenital malformation syndromes due to known exogenous causes. This code represents various birth defect syndromes caused by known environmental exposures during pregnancy, such as maternal infections, medications, or chemical exposures. Q86.8 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering other congenital malformations (q80-q89).
Q86.8 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Specify the known exogenous cause in the documentation (e.g., maternal rubella, maternal toxoplasmosis, specific medication).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q86.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Specify the known exogenous cause in the documentation (e.g., maternal rubella, maternal toxoplasmosis, specific medication)
- •Use additional codes to describe the specific malformations present for better clinical clarity