D-Dimer

Clinical Relevance:

D-Dimer tests are usually requested to help exclude, diagnose, and monitor diseases and conditions that cause hypercoagulability. One of the most common of these conditions is DVT, where DD is used as a negative predictive value in conjunction with a low Clinical Probability Score (CPS).

Measurements of D-Dimer may also be requested, along with other tests, to help diagnose DIC. DIC is a complex rapidly developing disease that can arise from a variety of situations including: some surgical procedures, burns, infections, cancer and liver disease.

Reference Range: Current laboratory (adult, M/F) normal ranges are as follows:
0.22 – 0.46 µg/mL (FEU).The cut-off for exclusion of VTE is < 0.50 µg/mL (FEU) in conjunction with a low Clinical Probability Score (CPS).
Min. Volume: The volume of blood in coagulation samples must lie within the volume range as indicated by the size of the black fill arrow present on tubes. Volumes above or below the arrow will result in sample rejection to ensure validity of results.
Turnaround Time: Urgent: 1 hour
Routine: 4 hours
Age of Sample: Samples will be rejected if received more than 4 hours after venepuncture.
Specimen Requirements:
  • 1 blue top (sodium citrate) sample.
  • All coagulation tubes must be adequately filled (see above).
  • All coagulation tubes must be mixed several times by gentle inversion immediately after venepuncture. Mixing the sample with the anticoagulant stops the sample clotting within the tube.
Limitations:
  • It is not possible to provide results on clotted, insufficient, haemolysed, or lipaemic samples. These will be rejected with the appropriate comment.
  • Sample tubes that have expired cannot be accepted.
  • D-Dimer results can be difficult to interpret when a patient is on anticoagulants.
Analysing Laboratory: Coagulation (JCUH and FHN)