DIC Syndrome Calculator - ISTH Overt DIC Score Tally

DIC syndrome, or disseminated intravascular coagulation, is a clinicopathological state in which widespread intravascular activation of coagulation consumes platelets and clotting factors faster than the body can replace them. The ISTH 2001 overt DIC score combines the platelet count, a D-dimer or fibrin-related marker, the prothrombin time prolongation, and the fibrinogen level into a 0 to 8 total. A score of 5 or more, in the presence of an underlying trigger condition, establishes overt DIC.

• • ICU and ER triage of suspected DIC: A septic, post-partum, or trauma patient with a falling platelet count and rising D-dimer needs a structured ISTH review at the bedside.
• • Hematology consult support: A hematology consult often asks for the ISTH score as the first step in a consumptive coagulopathy workup.
• • Obstetric consumptive coagulopathy workup: Antenatal or post-partum bleeding, placental abruption, amniotic fluid embolism, and severe preeclampsia can trigger DIC.
• • Teaching and protocol documentation: Trainees and pharmacists use the calculator to standardise the documentation of the four ISTH sub-scores in the chart.

A score of less than 5 does not rule DIC out in the first 24 to 48 hours of a trigger condition, so the calculator supports a repeat score.

Severe diabetic ketoacidosis with concurrent infection or hypoperfusion can drive a patient into the consumptive coagulopathy picture, and the Diabetic Ketoacidosis Calculator supports the parallel ADA 2009 severity review that runs alongside the ISTH score when DKA is part of the trigger workup.

The calculator walks through the four ISTH 2001 sub-scores, lets you pick the highest-matching option in each, and adds them into a 0 to 8 total. A total of 5 or more is read as overt DIC when an underlying trigger condition is present. The result is a structured review aid, not a treatment order.

• Platelets sub-score (0-2): Reflects the lowest recent platelet count: 0 if above 100, 1 if 50 to 100, 2 if below 50 (x 10^9 per litre).
• D-dimer sub-score (0-3): Reflects the rise in D-dimer or soluble fibrin monomer: 0 no increase, 2 moderate, 3 strong.
• PT prolongation sub-score (0-2): Reflects the difference between the patient's PT and the laboratory upper limit of normal: 0 under 3 s, 1 if 3 to 6 s, 2 if over 6 s.
• Fibrinogen sub-score (0-1): Reflects the fibrinogen level: 0 if 1 g/L or higher, 1 if below 1 g/L.

The numeric answer is a structured summary, not a treatment instruction. A 3 in D-dimer can dominate the result when sepsis drives strong fibrin turnover.

According to ISTH 2001 overt DIC criteria (Taylor et al., Thromb Haemost), the four sub-scores (platelets 0-2, D-dimer 0-3, PT prolongation 0-2, fibrinogen 0-1) sum to a maximum of 8, with 5 or more defining overt DIC when an associated disorder is present.

Because DIC is usually identified in the ICU or high-acuity ER, the APACHE II Score Calculator provides the parallel 12-variable acute-physiology severity review that helps the team judge how sick the patient with an overt ISTH score really is.

Each of the four ISTH sub-scores captures a different angle on the consumptive picture.

The four sub-scores are designed to be read together. A 3 in D-dimer without platelet consumption or PT prolongation suggests a non-DIC cause, while the same D-dimer with a falling platelet count and a prolonged PT is more concerning.

Once the ISTH score reaches 5 or more and bleeding or procedure risk appears, the Fresh Frozen Plasma Dose Calculator supports the volume and bag estimate that runs in parallel to the ISTH review and helps the team plan FFP replacement alongside cryoprecipitate.

Treat the calculator as a checklist that mirrors the ISTH 2001 criteria. Record each sub-score and the total so the next reviewer can challenge the inputs.

1. 1 Confirm an underlying trigger: Confirm sepsis, obstetric catastrophe, trauma, malignancy, or another DIC-associated trigger is present. The score is not designed for use without a clinical context.
2. 2 Pull the latest laboratory panel: Get the most recent platelet count, D-dimer or fibrin-related marker, PT (in seconds), and fibrinogen. Note the laboratory's upper limit of normal for PT.
3. 3 Score each of the four sub-scores: Pick the highest-matching option in each drop-down using the lowest count, the strongest D-dimer rise, the largest PT gap, and the lowest fibrinogen.
4. 4 Add the four sub-scores: Sum the four numbers into a 0 to 8 total. Read 5 or more as overt DIC; read 4 or less as not overt DIC and consider a repeat in 24 hours if the trigger is still active.
5. 5 Document the result in the chart: Record each sub-score, the total, the cutoff, and the underlying trigger so a later reviewer can challenge the inputs.

A 62-year-old with gram-negative sepsis, platelets 70, D-dimer strongly elevated, PT prolonged by 4 s, fibrinogen 1.3 g/L. Sub-scores 1, 3, 1, 0 total 5, the threshold for overt DIC. The team gives FFP and cryoprecipitate, treats the sepsis, and re-scores in 24 hours.

When the platelet fall that triggered the ISTH review is on a patient who is also on heparin, the 4TS Score helps the team rule out heparin-induced thrombocytopenia so the platelet consumption is not misattributed to a drug reaction.

An ISTH review can be done with a pen, but a calculator makes the tally consistent, traceable, and easier to defend.

• • Standardised review across providers: ER physicians, intensivists, hematologists, and pharmacists use the same four sub-scores, so the discussion depends less on memory.
• • Transparent record-keeping: Each sub-score and the total can be quoted in the chart note, so a later reviewer can challenge the inputs and confirm the cutoff.
• • Quick link to the ISTH cutoff: The calculator ties the total to the 5-point ISTH cutoff, so the user does not have to re-look up the threshold on a busy shift.
• • Encourages repeat scoring: The 'repeat in 24 hours' guidance keeps the consumptive picture from being forgotten.
• • Pairs with the trigger review: The result is most useful when paired with a structured review of the underlying sepsis, obstetric, trauma, or malignancy trigger.

The ISTH 2001 score was designed to make DIC easier to discuss at the bedside. The calculator keeps that goal front and centre but does not diagnose DIC or replace the trigger workup.

Because D-dimer is cleared renally and acute kidney injury is itself a complication of overt DIC, the GFR Calculator supports the bedside kidney review the team runs to interpret a borderline D-dimer sub-score and to anticipate renal replacement therapy needs.

Several things can move the DIC score up or down, and several conditions can mimic the laboratory pattern without true DIC.

• • The DIC syndrome score is a bedside rule, not a definitive diagnostic test. A low score does not rule out early DIC, and a high score in the wrong clinical context (liver failure without trigger) can over-call.
• • The ISTH 2001 criteria were validated for overt DIC. A separate non-overt DIC scoring system is meant for the earlier phase but is not part of this calculator.
• • The D-dimer cutoffs assume a standard assay. Different laboratories use different units and antibodies, so the cutoffs must be checked against the local reference range.

Bleeding risk, kidney function, and pregnancy status matter for what to do with the result, but the calculator stops at the score so the result stays a triage aid.

According to MedlinePlus - Disseminated Intravascular Coagulation (DIC), the consumptive picture is most often triggered by sepsis, obstetric complications, severe tissue injury, certain cancers, and liver disease, and treatment focuses on the underlying cause plus replacement of deficient clotting factors.

According to Merck Manual Professional Edition - Disseminated Intravascular Coagulation (DIC), severe rapidly evolving DIC is diagnosed by thrombocytopenia, prolonged PT and PTT, declining plasma fibrinogen, and elevated D-dimer, and is treated by correcting the underlying cause plus replacing platelets, cryoprecipitate, and fresh frozen plasma when bleeding is severe.

In obstetric and post-partum DIC, the underlying trigger review often runs alongside a venous thromboembolism risk assessment, and the VTE Risk Pregnancy Calculator supports the pregnancy-specific VTE review that pairs with the ISTH DIC score in the consumptive coagulopathy workup.