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Test Code DD D-Dimer, Plasma

Additional Codes

  • Expanse Test Name:D Dimer, P
  • Medinet Ref Code:DD
  • OV Code:COAG*DD

Performing Laboratory

St. Lukes Hospital Laboratory

Methodology

Immunoturbidimetric

Specimen Requirements

Draw blood in a light blue-top (3.2% sodium citrate) tube(s), and send 4.5 mL of sodium citrate whole blood. (Clotted or visibly hemolyzed specimen, specimen drawn in wrong tube, or tube that has less than expected fill is not acceptable.) If there is a delay in transport of >2 hours, spin down, separate plasma, and freeze in plastic vial.
Note:  1. Mix 9 parts of freshly drawn blood with 1 part of 3.2% sodium citrate anticoagulant. Invert tube gently 3 to 4 times immediately after venipuncture to ensure proper mixing of blood and anticoagulant.

2. If blood is drawn through an indwelling catheter, flush line with 5 mL of saline. Discard first 5 mL of blood or 6 dead space volumes of catheter, or use for other laboratory tests.

3. If blood is drawn with a butterfly set, a waste tube must be drawn to eliminate dead space of tubing to ensure adequate blood is drawn into coagulation tube.

Reference Values

Expected values for D-dimer are <0.59 mg/L for normal healthy patients according to the manufacturer and St. Luke’s Hospital Laboratories own limited reference range study of 31 healthy adults was <0.51 mg/L

 

The negative predictive value cutoff (NPVC), is 0.50 mg/L. Patients with a low clinical probability for pulmonary embolism (PE)/deep vein thrombosis (DVT) and a D-dimer assay result less than or equal to the NPVC likely do not have thromboembolic disease and a D-dimer result above the NPVC diagnostic studies should be considered. D-dimer levels are of little clinical utility for patients with a moderate-to-high clinical probability of thromboembolic disease since diagnostic studies will be performed on this group regardless of the D-dimer result. Measurement of D-dimer should not be used as an aid to the diagnosis of PE/DVT in patients with therapeutic dose anticoagulant therapy for >24 hours, fibrinolytic therapy within the previous 7 days, trauma or surgery within the previous 4 weeks, disseminated malignancies, aortic aneurysm, sepsis, severe infections, pneumonia, liver cirrhosis, or pregnancy.

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

CPT: 85379