From the Guidelines
Screening for Disseminated Intravascular Coagulation (DIC) requires a comprehensive panel of laboratory tests including complete blood count (CBC) with platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen level, D-dimer, and fibrin degradation products (FDPs). These tests should be ordered together as they provide complementary information about the coagulation system. In DIC, you typically see thrombocytopenia (low platelets), prolonged PT and aPTT, decreased fibrinogen, and elevated D-dimer and FDPs. Additional helpful tests include peripheral blood smear to assess for schistocytes (fragmented red blood cells), thrombin time, and specific factor assays like antithrombin III.
The most recent and highest quality study, 1, published in 2023, emphasizes the importance of early diagnosis of DIC, particularly in the context of sepsis, using a simple tool like the SIC scoring system. This system allows for the identification of patients with sepsis-associated DIC at an early stage, enabling timely intervention.
Serial measurements are important as DIC is a dynamic process, so these tests should be repeated every 6-12 hours in acute cases to monitor progression and response to treatment. The pattern of abnormalities helps distinguish DIC from other coagulopathies - the combination of consumption of clotting factors and platelets alongside increased fibrinolysis is characteristic of DIC. These tests reflect the pathophysiology of DIC, which involves inappropriate widespread activation of coagulation, consumption of clotting factors and platelets, and secondary fibrinolysis.
Other studies, such as 1 and 1, also support the use of these laboratory tests for the diagnosis of DIC, highlighting the importance of a comprehensive approach to screening. However, the most recent guidance from 1 takes precedence, emphasizing the role of early diagnosis and the SIC scoring system in managing sepsis-induced coagulopathy and DIC.
Key points to consider in the screening for DIC include:
- The use of a comprehensive panel of laboratory tests
- The importance of serial measurements in acute cases
- The role of the SIC scoring system in early diagnosis, particularly in sepsis
- The need for a timely and aggressive approach to addressing the underlying cause of DIC.
From the Research
Laboratory Tests for DIC Screening
The following laboratory tests are recommended for screening Disseminated Intravascular Coagulation (DIC):
- Platelet count: thrombocytopenia (platelet count < 100 x 10^3/μl) is a marker of DIC, but it should not be used as a single marker 2
- Prothrombin time (PT) and partial thromboplastin time (PTT): these tests are commonly used to diagnose DIC, but they have low sensitivity and specificity when used individually 3, 4
- Fibrinogen/fibrin degradation products (FDP) and D-dimer: these tests have high sensitivity and specificity for diagnosing DIC, and their combination is recommended for rapid and specific diagnosis 3
- Antithrombin: this test can provide insight into the severity and prognosis of DIC 3
- Thrombin-antithrombin complex (TAT) and plasmin-plasmin inhibitor complex (PPIC): these molecular markers may be useful for diagnosing DIC, especially in its early phase 5
Recommended Test Panels
The following test panels are recommended for DIC screening:
- D-dimer, FDP, and antithrombin: this panel provides a rapid and specific diagnosis, as well as insight into the severity and prognosis of DIC 3
- PT, PTT, FDP, and platelet count: this panel is commonly used, but it has lower sensitivity and specificity compared to the D-dimer, FDP, and antithrombin panel 3, 4
- TAT, PPIC, and D-dimer: this panel may be useful for diagnosing DIC, especially in its early phase, but it requires further confirmation 5