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Updates to D-dimer Reporting
In an effort to continuously provide accurate results and to improve test utilization based
on recent published recommendations, we are reviewing the form in which we report Ddimer results. Starting February 24th, 2015 we are using a different way to report DDimer results: instead of using d-dimer units (DDU) we will use fibrinogen-equivalentunits (FEU). The table below emphasis the differences between the current and the new
reporting format, including the units.
Parameter
Current
New
Reporting Unit
D-dimer units = ng/mL
Cut-off
250 ng/mL
No change
(Stago Liatest immuneturbidimetric assay)
Fibrinogen Equivalent Units =
ug/mL
0.50 ug/mL (500 ug/L)
No change
(Stago Liatest immuneturbidimetric assay)
No change
No change
No change
No change
Methodology
Specimen
requirements
Turn-aroundtime
Limitations
Conversion
factor
See below
See below
DDU x 2 / 1000 = FEU
Example: 450 ng/mL DDU = 0.225 ug/mL FEU
Current reporting interpretation:
Elevated D-Dimer levels suggest fibrinolysis of intravascular thrombi, causes of which
include pulmonary embolism, DVT, post surgical wound healing and trauma. Elevated
levels may also be seen in pregnancy, cancer, infection, and old age.
D-Dimer levels <250 ng/mL indicate a very low probability of intravascular thrombosis.
The actual range for a normal population is 100-250 ng/mL. The range stated above is
set at a cut-off level of 250 ng/mL and is optimized for sensitivity to low levels of DDimer. Levels can be much higher in DIC, but evaluation should include other
coagulation tests.
The cut-off range for excluding intravascular thrombosis is <250 ng/mL D-Dimer units.
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New reporting interpretation:
D-dimer Values in
FEU (ug/mL)
Interpretation
<0.50
DVT/PE Unlikely
Seen in ill patients but not diagnostic of
0.50-4.0
thrombosis
>4.0
Compatible with DIC but not diagnostic
>8.0
Strongly suggestive of DIC
Interfering substances that could lead to an overestimation of Ddimer include: Presence of rheumatoid factor >50 IU/ml
For questions, contact: Jessie Fisk (541-732-6314) or Jackie Strawn (541-7326662)