Dic Score Calculator

Calculate the ISTH disseminated intravascular coagulation score from labs. Enter values for instant results with step-by-step formulas.

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Formula

ISTH DIC Score = Platelet score (0-2) + Fibrin marker score (0-3) + PT score (0-2) + Fibrinogen score (0-1)

The ISTH scoring system assigns points for four laboratory parameters: platelet count (0 for >100K, 1 for 50-100K, 2 for <50K), fibrin-related markers like D-dimer (0 for normal, 2 for moderate, 3 for strong increase), PT prolongation (0 for <3s, 1 for 3-6s, 2 for >6s), and fibrinogen level (0 for >100 mg/dL, 1 for <100 mg/dL). Score of 5 or greater indicates overt DIC.

Worked Examples

Example 1: Overt DIC in Sepsis

Problem: A 65-year-old with gram-negative sepsis has platelets 45,000, D-dimer strongly elevated (>10x ULN), PT prolonged by 5 seconds, and fibrinogen 90 mg/dL. Calculate the ISTH DIC score.

Solution: Platelet count 45,000 (50-100K range): 1 point\nD-dimer strongly elevated: 3 points\nPT prolonged by 5 seconds (3-6 sec range): 1 point\nFibrinogen 90 mg/dL (<100): 1 point\nTotal ISTH DIC Score: 1 + 3 + 1 + 1 = 6\nThreshold for overt DIC: 5 or greater\nDiagnosis: Overt DIC

Result: ISTH DIC Score: 6/8 - Compatible with overt DIC; initiate treatment and repeat daily

Example 2: Non-Overt DIC Requiring Monitoring

Problem: A 42-year-old with acute pancreatitis has platelets 120,000, D-dimer moderately elevated, PT normal, and fibrinogen 180 mg/dL. Calculate the ISTH DIC score.

Solution: Platelet count 120,000 (>100K): 0 points\nD-dimer moderately elevated: 2 points\nPT not prolonged: 0 points\nFibrinogen 180 mg/dL (>100): 0 points\nTotal ISTH DIC Score: 0 + 2 + 0 + 0 = 2\nThreshold for overt DIC: 5 or greater\nDiagnosis: Not overt DIC, suggestive

Result: ISTH DIC Score: 2/8 - Suggestive but not overt DIC; repeat scoring in 1-2 days

Frequently Asked Questions

What is disseminated intravascular coagulation (DIC)?

Disseminated intravascular coagulation (DIC) is a serious and potentially life-threatening condition characterized by widespread activation of the coagulation cascade, leading to the formation of small blood clots throughout the vasculature. This pathological process simultaneously consumes clotting factors and platelets, paradoxically resulting in both thrombosis and hemorrhage. DIC is always a secondary condition triggered by an underlying disorder such as sepsis, severe trauma, obstetric complications, malignancy, or severe transfusion reactions. The condition can present acutely with dramatic bleeding or chronically with predominantly thrombotic manifestations. Early recognition and treatment of the underlying cause are the cornerstones of DIC management.

How does the ISTH DIC scoring system work?

The International Society on Thrombosis and Haemostasis (ISTH) developed a standardized scoring system for diagnosing overt DIC based on readily available laboratory tests. The scoring algorithm requires an underlying disorder known to be associated with DIC as a prerequisite. Four laboratory parameters are then scored: platelet count (0-2 points based on degree of thrombocytopenia), elevated fibrin-related markers such as D-dimer or fibrin degradation products (0-3 points), prolonged prothrombin time (0-2 points), and fibrinogen level (0-1 point). The maximum possible score is 8 points. A total score of 5 or greater is compatible with overt DIC, while a score below 5 is suggestive but not confirmatory, warranting repeat testing in 1-2 days.

What laboratory tests are used to diagnose DIC?

The diagnosis of DIC relies on a combination of laboratory tests that reflect the pathophysiology of simultaneous clotting and bleeding. The ISTH scoring system uses four key tests: platelet count to assess consumption, D-dimer or fibrin degradation products (FDPs) to detect ongoing fibrin formation and breakdown, prothrombin time (PT) to evaluate coagulation factor consumption, and fibrinogen level to assess this critical clotting protein. Additional useful tests include activated partial thromboplastin time (aPTT), thrombin time, antithrombin III levels, protein C levels, and peripheral blood smear showing schistocytes (fragmented red blood cells). Serial monitoring is essential because individual test values may be normal early in DIC, and trending is more informative than single measurements.

What are the most common causes of DIC?

DIC can be triggered by numerous underlying conditions across several categories. Infection and sepsis are the most common causes, accounting for approximately 30-40% of cases, with both bacterial (particularly gram-negative) and viral infections implicated. Trauma, including major surgery, burns, and crush injuries, is the second most common trigger through tissue factor release. Obstetric complications including placental abruption, amniotic fluid embolism, eclampsia, and retained dead fetus are important causes in the obstetric population. Malignancies, particularly acute promyelocytic leukemia, mucin-secreting adenocarcinomas, and other solid tumors can trigger DIC. Additional causes include severe transfusion reactions, vascular abnormalities such as large hemangiomas, envenomation from certain snake bites, and severe liver disease.

How is the treatment of DIC approached?

The treatment of DIC is primarily directed at managing the underlying cause while providing supportive care for the coagulation derangement. Treating the trigger, such as antibiotics for sepsis, delivery of the placenta in obstetric DIC, or chemotherapy for malignancy, is the single most important intervention. Supportive transfusion therapy includes platelet transfusion when counts fall below 10,000 or below 50,000 with active bleeding, cryoprecipitate to maintain fibrinogen above 100 mg/dL, and fresh frozen plasma when there is significant bleeding with prolonged PT. The role of heparin anticoagulation is controversial and generally reserved for cases with predominantly thrombotic manifestations such as purpura fulminans or venous thromboembolism. Antithrombin concentrate and recombinant activated protein C have been studied but are not standard treatments.

What is the difference between acute and chronic DIC?

Acute and chronic DIC represent different temporal presentations of the same pathological process with distinct clinical features. Acute DIC develops rapidly, often over hours, with dramatic bleeding manifestations including petechiae, ecchymoses, oozing from venipuncture sites, and mucosal bleeding. The laboratory profile shows marked thrombocytopenia, very elevated D-dimer, prolonged PT, and low fibrinogen. Acute DIC is most commonly associated with sepsis, major trauma, and obstetric emergencies. Chronic DIC, also called compensated DIC, develops gradually over weeks to months, allowing the liver to partially compensate for factor consumption. It more commonly presents with thrombotic complications rather than bleeding, and laboratory values may be only mildly abnormal. Chronic DIC is frequently associated with malignancies and retained dead fetus.