Test Code D Dimer D Dimer

Important Note

Tube must be properly filled.

Additional Codes

Cerner	NextGen
D Dimer	D Dimer

Useful For

D-dimer molecules are the terminal product of fibrin degradation and are derived from the action of plasmin, a fibrinolytic enzyme, on a fibrin clot. Their presence in plasma is evidence that the fibrinolytic system is active in response to coagulation activation. D-dimer is useful as a negative predictor in the exclusion of deep vein thrombosis (DVT) and pulmonary embolism (PE), is helpful in the diagnosis and management of DIC (typically D-dimer increases during DIC), and is involved in the activation states of coagulation (i.e. increased levels of D-dimer have been reported in post-operative periods, cancers, bleeding, and severe infections where fibrin formation has occurred which subsequently leads to enhanced fibrinolysis, causing D-dimer production).

Methodology

The STA®-Liatest D-Di test is an immuno-turbidmetric assay. D-dimer measurement is a photometric test based on the change in turbidity of a microparticle suspension. A suspension of latex microparticles coated with monoclonal antibodies for D-dimer is mixed with patient plasma. An antigen-antibody reaction occurs leading to agglutination of the latex particles which causes an increase in turbidity of the suspension, proportional to the concentration of D-dimer in the plasma. The increase in turbidity causes an increase in absorbance which is measured by photometry. The instrument automatically plots OD results on a standard curve and converts the results to µg/mL.

Patient Preparation

None

Collection Instructions

Sample collections must comply with the recommendations for hemostasis tests.
3.2% sodium citrate tubes only.
Tube must be properly filled.
Centrifuge within 4 hours of collection.

Specimen Requirements

Preferred Volume	1 mL plasma
Minimum Volume	1 mL plasma
Container	3.2% sodium citrate tube (blue top), BD or Greiner Vacutainer tubes
Stability	Specimens must be centrifuged and plasma removed within 4 hours of collection. Plasma Storage: 8 hours at 15-25⁰ C 1 month at -20⁰ C (thaw once at 37⁰ C); double-spin to create platelet poor plasma.
Rejection Criteria	Clotted Hemolyzed (refer to Limitations section) Lipemic (refer to Limitations section) Icteric (refer to Limitations section) Expired collection tube Under or Overfilled tube (blood/anticoagulant ratio must be 9:1; tube filled between 90-110 %) Improperly mixed specimen

Result Reporting and Reference Values

Reference Range	0 – 0.41 µg/mL FEU
Clinical Exclusion Cutoff Value for DVT and PE	≤ 0.5 µg/mL FEU, for patients with low or moderate pretest probability scores*
Critical Ranges	None

*Pretest probability (PTP) scores are based on Wells’ model for low, moderate, or high risk.

Reflex Testing