Disseminated Intravascular Coagulation - DIC

Diagnosis

Indications for Testing

  • Patient with risk factors for DIC along with bleeding or thrombocytopenia
  • Underlying disorder with known DIC association

Criteria for Diagnosis

  • Score global coagulation test results based on the following scoring system proposed by the International Society on Thrombosis and Hemostasis (ISTH)
    • Platelet count (x109/L)
      • (>100 = 0, 50-100 = 1, <50 = 2)
    • PT prolongation (seconds)
      • (<3 = 0, >3 but <6 = 1, ≥6 = 2)
    • Fibrinogen (g/L)
      • (>1 = 0, <1 = 1)
    • Fibrin-related markers (increase)
      • No increase = 0; moderate increase = 2; strong increase = 3
      • Cutoffs for scoring fibrin-related markers must be established for the specific assay
    • TOTAL
      • If ≥5, compatible with overt DIC – repeat scoring daily
      • If <5, suggestive of non-overt DIC – repeat scoring after 1-2 days

Laboratory Testing

  • CBC –  thrombocytopenia usually present (may be normal in early DIC)
  • Clotting times
    • Prothrombin time (PT) – prolonged (may be normal in early or chronic DIC)
    • Partial thromboplastin time (PTT) – prolonged (may be normal in early or chronic DIC)
    • Thrombin time (TT) – may be increased due to consumption of fibrinogen
  • Fibrin-related marker
    • D-dimer – increased in acute and chronic DIC (best single test)
      • Largely replaced fibrin degradation products (FDP) as a marker of coagulation
      • D-dimer measurements alone have excellent negative predictive value for DIC
      • Normal d-dimer essentially rules out DIC
      • Elevated d-dimer levels are seen in a number of conditions in addition to DIC (eg, pregnancy, acute thrombosis)
  • Coagulation factors
    • Fibrinogen – decreased

Differential Diagnosis

Clinical Background

Disseminated intravascular coagulation (DIC) is a disorder characterized by massive systemic activation of coagulation with consumption of platelets and coagulation proteins.

Epidemiology

  • Incidence – >18,000 cases annually in U.S.

Risk Factors

  • Sepsis (bacterial, viral, fungal)
  • Trauma (polytrauma, fat embolism, burns)
  • Malignancy (solid tumors, acute leukemia)
  • Obstetric complications (abruptio placentae, placenta previa, amniotic fluid embolus)
  • Toxic reactions (eg, venomous snake bite)
  • Immunologic reactions (hemolytic transfusion reaction, transplant rejection)
  • Organ destruction (pancreatitis, hepatic failure)

Pathophysiology

  • Activation of coagulation pathways
    • Generation of thrombin and formation of fibrin in circulating blood
    • Consumption of coagulation factors and platelets
  • Activation of inflammatory pathways via cytokines
  • Suppression of physiologic anticoagulant pathways
  • Activation and/or impairment of fibrinolysis

Clinical Presentation

  • Generally occurs in the setting of a risk factor listed above
  • Hemorrhage – petechiae, purpura, epistaxis, mucous membrane bleeding
  • Thrombosis – may lead to organ failure
  • Chronic DIC – occurs in cancer patients
    • Thrombosis is primary symptom
    • Referred to as Trousseau syndrome

Treatment

  • Treat underlying disorder causing DIC
  • Replacement therapy until underlying disorder resolved
    • Platelets
    • Fresh frozen plasma/cryoprecipitate
  • Patients with chronic DIC and thrombosis may require heparin therapy

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
CBC with Platelet Count 0040002
Method: Automated Cell Count

Screen for coagulation disorder; order concurrently with PT, PTT, TT, and fibrinogen

Normal result does not rule out DIC

 
Prothrombin Time 0030215
Method: Electromagnetic Mechanical Clot Detection

Screen for coagulation disorder; order concurrently with CBC, PTT, TT, and fibrinogen

Normal result does not rule out DIC

 
Partial Thromboplastin Time 0030235
Method: Electromagnetic Mechanical Clot Detection

Screen for coagulation disorder; order concurrently with CBC, PT, TT, and fibrinogen

Normal result does not rule out DIC

 
Thrombin Time with Reflex to Thrombin Time 1:1 Mix 0030260
Method: Electromagnetic Mechanical Clot Detection

Screen for coagulation disorder; order concurrently with CBC, PT, PTT, and fibrinogen

Normal result does not rule out DIC

 
Fibrinogen 0030130
Method: Electromagnetic Mechanical Clot Detection

Screen for coagulation disorder; order concurrently with CBC, PTT, and TT

Normal result does not rule out DIC

 
D-Dimer 0030057
Method: Immunoturbidimetry

Aid in diagnosing DIC

Presence of rheumatoid factor, pregnancy, acute thrombosis may lead to false-positive results

 
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Soluble Fibrin Monomer 0030126
Method: Qualitative Hemagglutination

Not recommended; order d-dimer test instead

Inhibitor Assay, PT with Reflex to PT 1:1 Mix 2003260
Method: Electromagnetic Mechanical Clot Detection
Inhibitor Assay, PTT with Reflex to PTT 1:1 Mix, with Reflex to 1-Hour Incubation 2003266
Method: Electromagnetic Mechanical Clot Detection
Fibrinogen Panel 0030137
Method: Electromagnetic Mechanical Clot Detection/Radial Immunodiffusion
Fibrin/Fibrinogen Degradation Split Products, Plasma 2006491
Method: Latex Agglutination

For fibrin degradation products (FDP) testing, this plasma test is the recommended test

For evaluating coagulopathies (eg, disseminated intravascular coagulation), D-dimer is the preferred test

Fibrin/Fibrinogen Degradation Split Products 0030140
Method: Latex Agglutination

This test is NOT recommended for FDP testing or for evaluating coagulopathies (eg, disseminated intravascular coagulation)

For FDP testing, the plasma FDP test, not the serum test,  is recommended; for evaluating coagulopathies, D-Dimer is the preferred test