Diagnosis of Disseminated Intravascular Coagulation (DIC)
DIC diagnosis requires both an underlying causative condition (sepsis, malignancy, trauma, or obstetric complications) and laboratory confirmation using validated scoring systems, with the ISTH overt DIC score (≥5 points) being the most widely accepted diagnostic tool. 1, 2
Diagnostic Approach
Step 1: Confirm Underlying Condition
DIC is never a primary disease but always secondary to an underlying disorder. 2 The most common triggers include:
- Sepsis (most common cause) 3
- Malignancy (particularly acute promyelocytic leukemia and solid tumors) 1
- Trauma 4
- Obstetric complications 5
Without an underlying condition, DIC cannot be diagnosed regardless of laboratory abnormalities. 6
Step 2: Apply ISTH Overt DIC Scoring System
The ISTH overt DIC criteria require ≥5 points for diagnosis: 1, 2
Platelet Count:
Fibrin-Related Markers (D-dimer or FDP):
Prothrombin Time:
- ≥6 seconds prolonged or PT ratio >1.4 = 2 points 2
- ≥3 to <6 seconds prolonged or PT ratio >1.2 to ≤1.4 = 1 point 2
Fibrinogen:
- <100 mg/dL = 1 point 2
Step 3: Consider Sepsis-Induced Coagulopathy (SIC) for Earlier Detection
For septic patients, the SIC scoring system enables earlier detection before overt DIC develops, requiring ≥4 points: 1, 2, 7
Platelet Count:
PT Ratio:
SOFA Score:
The SIC criteria are specifically designed for sepsis patients and should be used as a screening tool before progression to overt DIC. 1, 7 Patients with SIC have significantly higher mortality rates (approximately 24.8%) and may benefit from earlier intervention. 2, 7
Critical Diagnostic Considerations
Serial Monitoring is Essential
DIC is a dynamic process requiring repeated laboratory testing, not a single snapshot. 6, 4 A single normal result does not exclude DIC if clinical suspicion remains high. Monitor patients at risk with:
- Daily to monthly frequency depending on clinical context 1
- More frequent monitoring (every few hours) in acute, unstable situations 6
Cancer-Associated DIC Pitfalls
In malignancy-associated DIC, a platelet count in the "normal range" may still indicate DIC if it represents a ≥30% drop from baseline, particularly when baseline counts were elevated. 1 This is a commonly missed diagnostic clue. 1
Additionally, PT and PTT may remain normal in subclinical cancer-associated DIC when coagulation factors are only moderately decreased. 1 A ≥30% drop in platelet count should trigger DIC evaluation even without other laboratory abnormalities. 1
Sepsis-Associated DIC Characteristics
Unlike malignancy-associated DIC, sepsis-associated DIC features:
- Excessive suppression of fibrinolysis (not hyperfibrinolysis) 1
- Organ dysfunction predominates over bleeding due to microthrombotic complications 1
- Hypofibrinogenemia is uncommon in sepsis-associated DIC 1
- Platelet decline and PT prolongation correlate with mortality, while fibrin markers do not correlate with sepsis severity 1
Management Strategies
Priority 1: Treat the Underlying Condition
The cornerstone of DIC management is treating the underlying disorder—this is more important than any supportive measure. 1, 6 For example, early initiation of induction therapy in acute promyelocytic leukemia leads to rapid DIC resolution. 1
Priority 2: Supportive Care with Blood Products
Platelet Transfusion:
- Active bleeding: Maintain platelets >50 × 10⁹/L 1
- High bleeding risk (surgery/procedures): Transfuse if <30 × 10⁹/L in APL or <20 × 10⁹/L in other cancers 1
- Do NOT transfuse prophylactically based on laboratory values alone in non-bleeding patients without high bleeding risk 6
Fresh Frozen Plasma (FFP):
- Only for active bleeding with prolonged PT/aPTT: 15-30 mL/kg 1
- Do NOT give based on laboratory abnormalities alone 6
- If volume overload is a concern, use prothrombin complex concentrates (recognizing they only partially correct the defect) 1, 6
Fibrinogen Replacement:
- Only if fibrinogen <1.5 g/L persists despite FFP and patient has active bleeding 1
- Use cryoprecipitate (2 pools) or fibrinogen concentrate 1
Critical caveat: Transfused platelets and fibrinogen have very short lifespans in DIC due to ongoing consumption. 1
Priority 3: Anticoagulation in Specific Scenarios
Therapeutic-Dose Heparin Indications:
- Thrombosis-predominant DIC: arterial/venous thromboembolism, severe purpura fulminans with acral ischemia, or vascular skin infarction 6
- Prothrombotic solid tumors (in absence of contraindications like platelets <20 × 10⁹/L or active bleeding) 1
- Use continuous infusion unfractionated heparin (10 units/kg/h) for short half-life and reversibility in high bleeding-risk patients 6
Prophylactic-Dose Heparin:
- All critically ill, non-bleeding DIC patients should receive VTE prophylaxis with UFH or LMWH 6
- Subclinical DIC benefits from prophylactic heparin (avoid in hyperfibrinolytic DIC) 1
Do NOT use heparin in patients with active bleeding or severe thrombocytopenia (<20 × 10⁹/L). 1
Priority 4: Adjunctive Therapies (Limited Evidence)
Recombinant Activated Protein C:
- Consider in severe sepsis with DIC (24 mcg/kg/h continuous infusion for 4 days) 6
- Do NOT use if platelets <30 × 10⁹/L or high bleeding risk 6
- Note: This agent was withdrawn from the market due to increased bleeding risk without clear mortality benefit in broader sepsis populations 5
Antithrombin Concentrate:
Antifibrinolytic Agents:
- Generally contraindicated in DIC 6
- Exception: Primary hyperfibrinolytic DIC with severe bleeding may receive tranexamic acid (1 g every 8 hours) 6
Monitoring and Re-evaluation
Repeat laboratory testing is mandatory to assess response to treatment and disease progression. 6 The frequency depends on clinical stability:
No gold standard exists for DIC diagnosis, making clinical judgment essential when laboratory and clinical findings diverge. 1, 2