A Practical Guide to Haemostasis

ISTH DIC Scoring Algorithm:
Modifications for use in Pregnancy


DIC is a recognised cause of maternal mortality and a modification of the ISTH DIC Scoring algorithm was developed for use in pregnancy.  The modifications are necessary due to the changes in haemostasis that occur in normal pregnancy. The use of three components of the ISTH DIC score - Platelet count, Fibrinogen and differences in PT [compared to a normal laboratory control] allowed the development of an algorithm with a sensitivity of 88% and a specificity of 96% for the diagnosis of DIC. D-dimers were excluded as the levels rise in pregnancy and substantially after 20 weeks in pregnancy.

The ISTH DIC Score - Pregnancy:

Select Criteria:

Platelet Count
<50 x 109/L 1 Point
50 - 100 x 109/L 2 Points
100 - 185 x 109/L 1 Point
>185 x 109/L 0 Points
Prothrombin Time [PT] Difference [s]1
<0.5 0 Points
0.5 - 1.0 5 Points
1.0 - 1.5 12 Points
>1.5 25 Points
Fibrinogen [Clauss] Level
≤3.0 g/L 25 Points
3.0 - 4.0 g/L 6 Points
4.0 - 4.5 g/L 1 Point
≥4.5 g/L 0 Points

1Defined as the difference between the result of the patient and that of the laboratory normal control.


[Max score 52]

Interpretation of Score
≥26 Sensitivity of 88% and a specificity of 96% for the diagnosis of DIC

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