ICD-10 Code D66 – Hereditary factor VIII deficiency (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D66 – Hereditary factor VIII deficiency
What it is
D66 identifies inherited factor VIII deficiency, also known as hemophilia A. It is a bleeding disorder caused by reduced or absent factor VIII activity, leading to impaired clot formation.
Clinical signs
Clinical features vary; refer to documentation. Common findings include easy bruising, prolonged bleeding after injury or procedures, and recurrent bleeding into joints or muscles.
When to use this code
Use D66 when the provider documents hereditary factor VIII deficiency, hemophilia A, or congenital factor VIII deficiency. Apply it for confirmed inherited disease, including encounters for evaluation of bleeding episodes or chronic management. Do not use it for acquired factor VIII deficiency unless documentation clearly states a hereditary condition.
Do not use for
Do not use D66 for acquired hemophilia, nonspecific bleeding, or other coagulation disorders. Check documentation if the record only mentions low factor VIII without stating a hereditary diagnosis.
Coding tip
Confirm the chart states hereditary or congenital factor VIII deficiency before assigning D66.