Interpreting a DIC Panel
A DIC panel should be interpreted using the ISTH scoring system, which requires assessment of platelet count, prothrombin time, fibrinogen level, and D-dimer or fibrin degradation products, with a score ≥5 confirming the diagnosis of overt DIC. 1
Components of a DIC Panel
A complete DIC panel includes:
- Platelet count: Normal range 150-450 × 10^9/L
- Prothrombin time (PT): Normal range 11-14 seconds
- Fibrinogen: Normal range 2-4 g/L
- D-dimer or Fibrin/Fibrinogen Degradation Products (FDP): Normal D-dimer < 0.5 mg/L
ISTH Overt DIC Scoring System
The International Society on Thrombosis and Haemostasis (ISTH) scoring system is the most widely used method for interpreting DIC panels:
| 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 ≥5 confirms overt DIC 1
Clinical Interpretation
When interpreting a DIC panel, consider:
Underlying condition: DIC always occurs secondary to an underlying disorder such as sepsis, trauma, malignancy, or obstetric complications 1
Clinical presentation: DIC can present with:
- Procoagulant form: Excess thrombin causing thrombosis
- Hyperfibrinolytic form: Dominated by bleeding
- Subclinical form: Laboratory abnormalities without obvious clinical manifestations 2
Serial monitoring: A single DIC panel is insufficient; repeated testing is essential to monitor the dynamic changes in coagulation parameters 3
Alternative Scoring Systems
For specific clinical scenarios, consider alternative scoring systems:
Sepsis-Induced Coagulopathy (SIC) Score: For earlier detection of coagulopathy in sepsis patients
- Platelet count, PT ratio, and SOFA score
- Score ≥4 indicates SIC 1
Japanese Association for Acute Medicine (JAAM) DIC Score: Specifically designed for sepsis and trauma-associated DIC 1
Diagnostic Efficiency of DIC Tests
The combination of D-dimer and FDP tests offers the highest diagnostic efficiency (95%) with 91% sensitivity and 94% specificity 4. Individual tests have lower efficiency:
- FDP alone: 87% efficiency
- PT/PTT + FDP: 86% efficiency
- D-dimer alone: 80% efficiency
- PT, PTT, thrombin time, platelet count, and fibrinogen individually have lower efficiency (57-70%) 4
Common Pitfalls in DIC Panel Interpretation
Relying solely on INR for non-warfarin patients can be misleading 1
Misinterpreting normal coagulation screens: A normal PT/aPTT does not exclude DIC, especially in subclinical forms 1
Overlooking the clinical context: Laboratory abnormalities must be interpreted in the context of the underlying condition 1
Failing to repeat tests: Single measurements may miss the dynamic nature of DIC 3
Confusing DIC with other conditions: Such as thrombotic thrombocytopenic purpura (TTP) or disseminated intravascular microthrombosis (DIT) 5
By systematically applying the ISTH scoring system to the DIC panel results and considering the clinical context, you can accurately diagnose DIC and guide appropriate management decisions to improve patient outcomes.