Disseminated intravascular coagulation Diagnosis
DIC is a very complex condition that can be hard to diagnose. No one test is sensitive and specific enough to diagnose DIC. In some cases, several different tests given over a period of time may be needed for an accurate diagnosis. This condition is suggested by the following combination:
A health professional may suspect DIC in a person who has symptoms of excessive bleeding or clotting. Blood tests to measure the amount of platelets and other substances (such as prothrombin and fibrinogen) that affect clotting can help confirm the diagnosis.
In severe cases with increased bleeding, some of these tests may be performed:
D-dimer test. This blood test helps determine whether a person's blood is clotting normally by measuring a substance (fibrin) that is released as a blood clot breaks up. D-dimer levels are often higher than normal in people who have abnormal blood clotting. The D-dimer test gives strong evidence of DIC.
Prothrombin time (PT/INR). This blood test measures how long it takes blood to clot. At least a dozen blood proteins, or clotting factors, are needed to clot blood and stop bleeding (coagulation). Prothrombin, or factor II, is one of several clotting factors produced by the liver. A long prothrombin time can be a sign of DIC.
Fibrinogen. This blood test measures how much fibrinogen is in the blood. Fibrinogen is a protein that plays a part in blood clotting. A low fibrinogen level can be a sign of DIC. It happens when the body is using fibrinogen faster than the body can make it.
Complete blood count (CBC). A complete blood count (CBC) involves taking a blood sample and counting the number of red blood cells and white blood cells. CBC results cannot diagnose DIC, but they provide information to help the doctor make a diagnosis. (DIC often causes the platelet count to drop.)
Blood smear. In this test, a drop of blood is smeared on a slide and stained with a special dye. The slide is then examined under a microscope. The number, size, and shape of red blood cells, white blood cells, and platelets are recorded. Blood cells often look damaged and abnormal in people with DIC.
In acute disseminated intravascular coagulation PT and aPTT are prolonged, and the platelet count and fibrinogen decrease. D-dimer, FDP, and fibrin monomer levels are elevated. In mild or chronic disseminated intravascular coagulation without bleeding, DIC PT and aPTT may be prolonged or normal. The fibrinogen level is decreased modestly and, in some cases, may be within the reference range or increased. Platelets may be slightly low or normal. D-dimer and FDP are slightly elevated.
Other tests may be useful but do not confirm the diagnosis, include: