Synonyms

DDIM

Clinical Indications

To aid diagnosis of DVT in association with a pre-test clinical score.
D-dimer has been validated for DVT only and is not suitable for other diagnoses, including pulmonary embolism.

Part of Profile

A coagulation screen should be requested if anticoagulation is contemplated.

Request Form 

Combined Pathology Blood form (Yellow/Black or Blue for GP's)

Availability

On request.

Specific Criteria

A pre-test clinical score should be undertaken before requesting D-dimer.

Turnaround Time

2 hours

Specimen

Citrated Blood  

Volume

Collection tube must be filled to 'fill mark' on side of bottle. This is critical.

Container

Blue top (sodium citrate) tube

Collection

Haemolysis or stasis during venepuncture should be avoided.

Lab. Handling

Samples should be processed as soon as possible.

Causes for Rejection

Unlabelled sample
Not meeting specific criteria for analysis. 
Delay in sample reaching laboratory
Underfilled, clotted or haemolysed samples. 

Reference Range

For investigation of DVT and PE D-dimer test should only be interpreted when there is a low clinical suspicion or score (see report for more detail). In published reports a level below 189 has been shown to exclude DVT with a sensitivity of 95%. A level below 189 combined with a low clinical score (less than or equal to 1) excludes DVT with a sensitivity of 100%. For investigation of DIC, a D-dimer <200 is normal, a level >2,000 is consistent with DIC.