Which laboratory findings are typical of DIC?

• A. Prolonged prothrombin time, decreased fibrinogen, decreased platelets, and elevated D-dimers.
• B. Normal PT, elevated fibrinogen, increased platelets, normal D-dimers.
• C. Shortened PT, increased fibrinogen, increased platelets, decreased D-dimers.
• D. Prolonged aPTT only with normal platelets and fibrinogen.

Answer: (A)

DIC is a consumptive coagulopathy where widespread activation of clotting uses up platelets and coagulation factors, with simultaneous increased fibrinolysis. Because clotting factors and platelets are consumed, coagulation tests often become prolonged and the platelet count drops. Fibrinogen is consumed to form fibrin, so its level falls. As clots form and are broken down, fibrin degradation products rise, so D-dimer is elevated.

The pattern described—prolonged PT, low fibrinogen, low platelets, and high D-dimer—fits this picture best. The other patterns don’t match DIC: having normal PT with high fibrinogen and platelets, or a shortened PT with high fibrinogen and platelets, or seeing only prolonged aPTT with normal platelets and fibrinogen, would not reflect the widespread consumption and active fibrinolysis characteristic of DIC.