Calculators · Haematology · Criteria
ISTH overt DIC score (2025 revision)
Also called ISTH DIC score, disseminated intravascular coagulation score, overt DIC
Diagnoses overt (late-phase) DIC in a patient with a disorder known to cause it, using the 2025 ISTH update with defined D-dimer cut-offs.
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Formula and scoring
Platelets ≥100 = 0, 50–<100 = 1, <50 = 2. D-dimer/FDP ≤3× ULN = 0, >3× = 2, >7× = 3. PT prolongation <3 s = 0, 3–<6 s = 1, ≥6 s = 2. Fibrinogen <1 g/L (100 mg/dL) = 1. Overt DIC ≥5.
Exam and ward pearls
- The 2025 update changed only the fibrin-marker item: the 2001 "moderate" and "strong" increase became >3× and >7× the upper limit of normal.
- Score only a patient with a condition that can cause DIC; the score does not identify the cause.
When not to rely on it
- Overt DIC criteria identify late-phase DIC; for sepsis use the SIC score to detect earlier coagulopathy.
- D-dimer assays and units (FEU vs DDU) vary; always express the result against your own laboratory ULN.
Source
- Iba T, Levy JH, Maier CL, Helms J, Umemura Y, Moore H, et al. Updated definition and scoring of disseminated intravascular coagulation in 2025: communication from the ISTH SSC Subcommittee on Disseminated Intravascular Coagulation. J Thromb Haemost. 2025;23(7):2356-62. doi:10.1016/j.jtha.2025.03.038 · PMID 40216223
- Taylor FB Jr, Toh CH, Hoots WK, Wada H, Levi M. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost. 2001;86(5):1327-30. PMID 11816725
Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.