ReadyCalculator
MathPhysicsFinanceConstructionBiologyChemistryConversionEcologyEveryday LifeFoodHealthSportsStatisticsOther

ISTH DIC Score

Select the option that best matches each laboratory value. The ISTH scoring tool totals the points to classify the probability of overt disseminated intravascular coagulation.

Platelet count (x10^9/L)

Fibrin-related markers (D-dimer, FDP)

Prolongation of PT (seconds)

Fibrinogen (g/L)

ISTH score

6

Interpretation

Overt DIC likely

Score 5 or higher suggests overt DIC by ISTH criteria. Address the underlying trigger, monitor labs frequently, and provide blood product support based on bleeding risk.

How to Use This Calculator

1

Collect laboratory data

Use platelet count, fibrin degradation products (such as D-dimer), PT prolongation, and fibrinogen values obtained on the same blood draw when possible.

2

Select matching categories

Pick the option closest to the reported value for each lab test. The calculator assigns points automatically following ISTH criteria.

3

Interpret and act

Scores 5 or greater indicate overt DIC. Integrate the score with clinical context, bleeding or thrombosis risk, and initiate treatment of the cause.

Formula

Total score = Platelet points + Fibrin marker points + PT points + Fibrinogen points

  • Platelets: >100 (0), 50-100 (1), <50 (2)
  • Fibrin markers: None (0), Moderate increase (2), Strong increase (3)
  • PT prolongation: <3 seconds (0), 3-6 seconds (1), >6 seconds (2)
  • Fibrinogen: >1.0 g/L (0), <=1.0 g/L (1)

Interpretation: Score >=5 = overt DIC; Score <5 = non-overt DIC.

Full Description

Disseminated intravascular coagulation is a systemic activation of coagulation that can cause both bleeding and thrombosis. The ISTH scoring system combines platelet count, fibrin markers, PT prolongation, and fibrinogen concentration to standardise diagnosis. Use this calculator to support clinical decision making, monitor trends, and evaluate response to treatment while addressing the underlying disorder.

Frequently Asked Questions

Which conditions commonly cause DIC?

Sepsis, trauma, malignancy, obstetric emergencies, severe liver disease, and massive transfusion can precipitate DIC.

Does a low score exclude DIC?

A score below 5 indicates non-overt DIC, but repeat testing is recommended if clinical suspicion persists.

How often should laboratory values be repeated?

In unstable or critically ill patients, reassess every 6 to 24 hours depending on disease severity and progression.

Why can fibrinogen remain normal?

Early DIC may not yet produce significant fibrinogen consumption. Falling levels, especially near or below 1.0 g/L, support overt DIC.