What are the diagnostic criteria for Disseminated Intravascular Coagulation (DIC)?

Diagnostic Criteria for Disseminated Intravascular Coagulation (DIC)

The International Society on Thrombosis and Haemostasis (ISTH) overt DIC scoring system is the global standard for diagnosing DIC, requiring a score of ≥5 points based on platelet count, fibrin-related markers, prothrombin time, and fibrinogen levels. 1

ISTH Overt DIC Scoring System

• Platelet count:

  • 2 points: <50 × 10^9/L
  • 1 point: ≥50, <100 × 10^9/L 1

• Fibrin-related markers (D-dimer or FDP):

  • 3 points: Strong increase
  • 2 points: Moderate increase 1

• Prolonged prothrombin time (PT):

  • 2 points: ≥6 seconds above normal or PT ratio >1.4
  • 1 point: ≥3 seconds, <6 seconds above normal or PT ratio >1.2, ≤1.4 1

• Fibrinogen level:

  • 1 point: <100 mg/dL 1

• Total score for DIC diagnosis: ≥5 points 1

Sepsis-Induced Coagulopathy (SIC) Scoring System

For earlier detection of DIC specifically in sepsis patients, the ISTH recommends using the SIC scoring system:

• Platelet count:

  • 2 points: <100 × 10^9/L
  • 1 point: ≥100, <150 × 10^9/L 1

• Prothrombin time (PT ratio):

  • 2 points: >1.4
  • 1 point: >1.2, ≤1.4 1

• SOFA score (Sequential Organ Failure Assessment):

  • 2 points: ≥2
  • 1 point: 1 1

• Total score for SIC diagnosis: ≥4 points 1

Two-Step Sequential Approach for Sepsis Patients

The ISTH recommends a two-step approach for diagnosing coagulopathy in sepsis:

1. First screen for SIC (compensated phase)
2. Then assess for overt DIC (decompensated phase) 1

This sequential approach allows for earlier identification and potential intervention before progression to full DIC 1.

Clinical Importance and Considerations

• DIC is not a primary disease but a syndrome secondary to underlying conditions such as sepsis, trauma, malignancy, or obstetrical complications 1, 2

• The mortality of septic patients with DIC is approximately 24.8%, highlighting the importance of early diagnosis 1

• Different types of DIC exist based on the underlying cause:

  • Sepsis-associated DIC: characterized by excessive suppression of fibrinolysis and organ dysfunction 1
  • Malignancy-associated DIC: more commonly presents with bleeding 1, 2
  • Trauma-associated DIC: characterized by hyperfibrinolysis 2

• No gold standard for DIC diagnosis exists, making definitive comparison of diagnostic accuracy between different scoring systems challenging 1

• Repeated testing is essential as DIC is a dynamic process that evolves over time 3, 2

Emerging Considerations

• Endothelial injury is an essential component of DIC pathophysiology but is not included in current diagnostic criteria 1

• Potential endothelium-related biomarkers that may improve future diagnostic criteria include:

  • Antithrombin activity
  • von Willebrand factor 1

• The ISTH is exploring the possibility of incorporating endothelium-related markers into diagnostic criteria to enable earlier detection and better management of DIC 1

Common Pitfalls to Avoid

• Relying solely on laboratory tests without considering the clinical context and underlying condition 3, 2

• Failing to repeat tests to monitor the dynamically changing scenario 3, 2

• Using the same diagnostic criteria for all types of DIC despite different underlying pathophysiologies 2, 4

• Delaying diagnosis by waiting for all classic manifestations to appear rather than using established scoring systems 3, 2