Pathology Handbook

D-dimer

Synonyms

DD, FDP

Clinical Indications

Suspicion of DIC or to aid the exclusion of VTE in association with a pre-test clinical score (please the hospital intranet for DVT assessment guidelines for clinical scoring)

Request Form 

ICE request

Availability

Daily

Specific Criteria

A pre-test clinical score MUST be undertaken before requesting D-Dimer in cases of VTE

Patient Preparation

Patient should ideally be at rest.

Turnaround Time

Same day

Specimen

Fresh citrated Blood; sample must be received by the laboratory within 4 hours of collection.

Volume

4.5ml citrated blood

Container

4.5 ml blue citrated bottle

Vacutainer blue top

Collection

Clean venepuncture. Samples must be received by the laboratory within 4 hours of collection.

Causes for Rejection

Underfilled, clotted, haemolysed or if sample is too old.

Failure to report the pre test clinical score on ICE requesting

Reference Range

A D-Dimer of <230ng/ml, together with a low clinical suspicion (score) of VTE, significantly reduces the likelihood of DVT (in non-anticoagulated patients).

If the clinical suspicion (score) of DVT is moderate/ high, then the D-Dimer result is not diagnostically helpful.