What does a Disseminated Intravascular Coagulation (DIC) panel consist of?

Components of a DIC Panel

A Disseminated Intravascular Coagulation (DIC) panel consists of platelet count, prothrombin time (PT), fibrinogen level, and fibrin/fibrinogen degradation products (FDP) or D-dimer. 1

Core Laboratory Tests in DIC Panel

The standard DIC panel includes the following components:

1. Platelet Count

   • Normal range: 150-450 × 10^9/L
   • DIC range: <50 × 10^9/L (severe), 50-100 × 10^9/L (moderate) 1, 2

2. Prothrombin Time (PT)/PT Ratio

   • Normal range: 11-14 seconds / 0.9-1.1
   • DIC significance:
     • PT prolongation ≥6 seconds (severe)
     • PT prolongation 3-6 seconds (moderate) 1
     • PT ratio >1.4 (severe), 1.2-1.4 (moderate) 1

3. Fibrinogen Level

   • Normal range: 2-4 g/L
   • DIC significance: <1 g/L 1, 2

4. Fibrin-Related Markers

   • D-dimer (preferred) or FDP
   • Normal D-dimer: <0.5 mg/L
   • DIC significance: Strong or moderate increase 1, 2

Additional Tests Often Included

While not part of the core scoring criteria, these tests are frequently added to provide a more comprehensive assessment:

• Activated Partial Thromboplastin Time (aPTT) 3, 4
• Thrombin Time 3
• Peripheral Blood Smear (to detect schistocytes/fragmented RBCs) 3
• Antithrombin Activity (provides insight into severity and prognosis) 3, 2

Diagnostic Scoring Systems

The International Society on Thrombosis and Haemostasis (ISTH) has established scoring systems for DIC diagnosis:

1. ISTH Overt DIC Scoring System

   • Requires a score ≥5 points based on:
     • Platelet count
     • PT prolongation
     • Fibrinogen level
     • Fibrin-related markers (D-dimer/FDP) 1

2. Sepsis-Induced Coagulopathy (SIC) Scoring System

   • Detects earlier stages of coagulopathy in sepsis
   • Includes SOFA (Sequential Organ Failure Assessment) score
   • Requires a score ≥4 points 1

Test Efficiency Considerations

Research has shown that certain test combinations offer superior diagnostic efficiency:

• D-dimer + FDP combination: Highest diagnostic efficiency (95%), with 91% sensitivity and 94% specificity 3
• FDP alone: 87% efficiency, 100% sensitivity, 67% specificity 3
• PT/PTT + FDP combination: 86% efficiency, 91% sensitivity, 71% specificity 3

Clinical Considerations

• Serial measurements are essential as DIC is a dynamic process 4
• Normal coagulation screens do not exclude DIC, especially in subclinical forms 2
• The DIC panel should be interpreted in the context of the underlying clinical condition 4

Practical Approach to DIC Diagnosis

1. Identify patients at risk (sepsis, trauma, malignancy, obstetric complications)
2. Order the complete DIC panel
3. Calculate the DIC score using ISTH criteria
4. Monitor changes in laboratory parameters over time
5. Interpret results in the context of the clinical presentation

By systematically evaluating these parameters, clinicians can accurately diagnose DIC and monitor response to treatment, ultimately improving patient outcomes.