D-dimer

Alternative names, keywords

Fibrin degradation products, FDP, D-dimers.

Samples required

Trisodium citrate blood (blue cap, 3.5 mL tube) taken with minimal stasis, filled to the line. Smaller tubes are available for paediatric samples.

Samples must be analysed or processed in the laboratory within 8 hours of venepuncture.

Samples must be no more than 8 hours old for add-on requests.

Test indications

Degradation product of crosslinked (by factor XIII) fibrin, reflects ongoing activation of the haemostatic system.

Reference range

< 0.5 µg/mL FEU (Fibrinogen Equivalent Units*) up to the age of 50 years.

For results in individuals over the age of 50 years an age-adjusted reference range is reported. This is based on current clinical guidance and for reference is Age x 0.01 µg/mL so that, for example, for an 82 yr old would be < 0.82 µg/mL FEU.

_{Source: locally determined.}

Unable to report on samples from pregnant patients or patients on anticoagulant therapy.

*Quantitative D-dimer assay result can be reported as either concentration of D-dimer or as FEUs, depending on the calibration method. The two numerical values are easily convertible to each other, since the mass of one unit of FEU equals approximately half of one D-dimer unit (D-DU):

1 FEU = 2 X D-DU

For example, 0.5 µg/mL FEU = 0.25 µg/mL D-DU.

Turnaround time

1 working day (2 hours if identified as urgent)

Enquiries

Haematology (Coagulation)