BOF: Clotting (DIC)

Which ONE of the following statements regarding the laboratory diagnosis of disseminated intravascular coagulation (DIC) is correct?

a) Activated partial thromboplastin time and prothrombin time are abnormal in >70% of cases.

b) Fibrin degradation products (FDPs) are increased in renal impairment.

c) Most patients have hypofibrinogenemia

d) The presence of thrombocytopenia with fragmented red cells on the blood film confirms the diagnosis.

e) Thrombocytopenia is a late manifestation.

Answer:

b) Fibrin degradation products (FDPs) are increased in renal impairment.

Explanation:

DIC is due to widespread uncontrolled activation of coagulation and thrombin generation with microangiopathic haemolysis, thrombocytopenia and consumption of clotting factors and fibrinogen leading to a bleeding diathesis. Thrombocytopenia is the most commonly detected abnormality (in 60% of cases) and occurs early in DIC, while PT and APTT may be normal or even reduced (in around 50% of cases), particularly in its early stages when excess thrombin generation may influence these laboratory parameters even with deficit of other clotting factors. Excess red cell fragments raises the possibility of thrombotic thrombocytopenic purpura, a far more dangerous condition, and other elements of the syndrome should be excluded. FDPs are metabolised in the liver, excreted via the kidney and increased in renal failure.

Reference:

Levi M, Toh CH, Thachil J, Watson HG. Guidelines for the diagnosis and management of disseminated intravascular coagulation. British Committee for Standards in Haematology. Br J Haematol 2009; 145:24.

Note addendum: Jecko Thachil, Cheng Hok Toh, Marcel Levi, Henry G Watson, The withdrawal of Activated Protein C from the use in patients with severe sepsis and DIC [Amendment to the BCSH guideline on disseminated intravascular coagulation], British Journal of Haematology, 2012, 157, 4