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
Guidance on Laboratory testing for Heritable Thrombophilia
Detailed information and guidance on “VTE Prophylaxis in Pregnancy and the Puerperium” is available
on the Intranet in the maternity section of Policies.
(Last reviewed July 2024)