Which set of factors comprises the Virchow triad?

• A. Endothelial injury only
• B. Abnormal blood flow only
• C. Hypercoagulability only
• D. Injury to the blood vessel endothelium, abnormalities of blood flow, and hypercoagulability

Answer: (D)

The Virchow triad describes three conditions that promote thrombosis: injury to the lining of a blood vessel (endothelial injury), abnormalities in blood flow (such as stasis or turbulence), and a tendency of the blood to clot more readily (hypercoagulability). Endothelial injury exposes underlying structures like collagen and tissue factor, triggering platelet adhesion and activation of the coagulation cascade. Abnormal flow—especially stasis—fails to wash away activated clotting factors and platelets, allowing them to accumulate and form a clot. Hypercoagulability can be inherent or acquired, tipping the balance toward clot formation. Together, these factors create a environment that greatly favors thrombosis, and the triad is defined by the presence of all three components. The other options only mention a single factor, which is not sufficient to describe the full triad.