In this section
The ISTH group produced a simple scoring system for the diagnosis of DIC depending on the Platelet count, the PT, the fibrinogen level and critically the FDP/D-Dimer results:
| Parameter | Result | Score |
| 1. Platelet count |
>100×109/l <100×109/l < 50×109/l |
0 1 2 |
| 2. PT |
<3s prolonged >3s but <6s >6s |
0 1 2 |
| 3. Fibrinogen |
>1.0g/l <1.0g/l |
0 1 |
| 4. FDP/D-Dimer |
No increase Moderate increase Strong increase |
0 2 (250-5,000) 3 (>5,000) |
A total score of ≥5 = DIC as long as the score is associated with a clinical disorder known to cause DIC. If the score is ≥5 you must ring the ward/medic and make them aware of the risk of DIC.
Guidance note: D-dimer testing in the diagnosis of venous thromboembolism (VTE) in hospital patients
- VTE is highly unlikely in patients who are judged by means of a clinical scoring system to be clinically unlikely to have VTE, and who have a negative D-dimer test.
- D-dimer testing has very limited usefulness to aid diagnosis in patients where the clinical probability of VTE is high.
- D-dimer is frequently raised in hospital inpatients without VTE.
- D-dimer is increased in infection, cancer, inflammation, surgery, trauma, ischaemic heart disease, stroke, pregnancy, sickle cell disease & trait.
- D-dimer testing is not useful in the diagnosis of VTE in patients with concomitant diseases.
- There is a decrease in the specificity of D-dimer testing for VTE with increasing age (i.e. D-dimer testing is less reliable in older patients).
- D-dimer should not be used to exclude VTE in children. The negative predictive value of D-dimer in children with suspected VTE has not been validated and levels may vary with age.
Guidance
- D-dimer testing should only be requested in patients with a low clinical probability of VTE, or in the assessment of recurrence risk for VTE post completion of anticoagulant therapy.
- In patients with a high clinical probability of VTE, or in patients with co-existing illness, D-dimer testing is unlikely to add any useful diagnostic value and should not be requested.
Reference
Thacil J et al, Appropriate use of D-dimer in hospital patients. Am J Med 2010, 123, 17-9.
- Guidance on Laboratory testing for Heritable Thrombophilia is available to view on the Trust intranet
- Detailed information and guidance on “Thromboprophylaxis in Pregnancy and the Puerperium” is available on the Intranet in the maternity section of Policies
(Last reviewed January 2023)