What are the 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 requires a score ≥5 points based on platelet count, prothrombin time, fibrinogen level, and fibrin-related markers to diagnose DIC. 1, 2

ISTH Overt DIC Scoring System

Parameter	Score	Range
Platelet count (×10⁹/L)	2	<50
	1	≥50, <100
Fibrin-related markers (D-dimer/FDP)	3	Strong increase
	2	Moderate increase
Prothrombin time (PT)	2	≥6 seconds prolongation (PT ratio >1.4)
	1	≥3 seconds, <6 seconds prolongation (PT ratio >1.2, ≤1.4)
Fibrinogen (g/L)	1	<1.0
Total score for DIC diagnosis	≥5

Sepsis-Induced Coagulopathy (SIC) Scoring System

For early detection of coagulopathy in sepsis, the ISTH developed the SIC scoring system which requires a score ≥4 points 1:

Parameter	Score	Range
Platelet count (×10⁹/L)	2	<100
	1	≥100, <150
PT ratio	2	>1.4
	1	>1.2, ≤1.4
SOFA score	2	≥2
	1	1
Total score for SIC diagnosis	≥4

Clinical Approach to DIC Diagnosis

1. Identify underlying condition

   • DIC always occurs secondary to an underlying disorder (sepsis, trauma, malignancy, obstetric complications) 1
   • The presence of a compatible clinical condition is essential for diagnosis

2. Laboratory evaluation

   • Complete DIC panel including:
     • Platelet count
     • Prothrombin time (PT)
     • Fibrinogen level
     • D-dimer or fibrin/fibrinogen degradation products (FDP)

3. Serial monitoring

   • Repeat laboratory tests to monitor the dynamically changing scenario 3
   • DIC is often a rapidly evolving condition requiring frequent reassessment

Different DIC Scoring Systems

Several scoring systems exist for DIC diagnosis:

1. ISTH Overt DIC Score - Most widely used internationally 1
2. Japanese Association for Acute Medicine (JAAM) DIC Score - Commonly used in Japan, designed specifically for sepsis and trauma-associated DIC 1
   • Eliminates fibrinogen scoring
   • Adds systemic inflammatory response syndrome (SIRS) scoring
   • Includes platelet count changes
3. Sepsis-Induced Coagulopathy (SIC) Score - Designed for earlier detection of coagulopathy in sepsis 1

Clinical Pearls and Pitfalls

• Serial testing is crucial - DIC is a dynamic process, and a single set of laboratory values may not capture the evolving nature of the condition 3

• Normal coagulation screens do not exclude DIC - Especially in subclinical or early forms 2

• Consider the type of DIC - DIC can be categorized into bleeding, organ failure, massive bleeding, and non-symptomatic types based on the balance between hypercoagulation and hyperfibrinolysis 4

• Underlying condition dictates management - Treatment of the underlying condition is the cornerstone of DIC management 3

• Avoid relying solely on INR - INR was designed specifically for warfarin monitoring and can be misleading in DIC 2

• Laboratory values must be interpreted in clinical context - The diagnosis should encompass both clinical and laboratory information 3

By using these standardized scoring systems and understanding the pathophysiology of DIC, clinicians can make timely diagnoses and initiate appropriate management to reduce morbidity and mortality associated with this complex coagulation disorder.