D-Dimer

Casandra

Casandra Test Code LC38648Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 115188CPT Code 85379

Clinical Use

Use

The Innovance® D-dimer assay is intended for use in conjunction with a nonhigh clinical pretest probability (PTP) assessment model to exclude deep vein thrombosis (DVT) and pulmonary embolism (PE).6 This test can be used to exclude VTE with nonhigh pretest probability (ie, low or low/moderate pretest probability). In an exclusion strategy, a D-dimer below the established threshold in a nonhigh pretest probability patient does not require further testing to exclude VTE.

Special Instructions

If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions. Patient samples may contain heterophilic antibodies (e.g., human anti-mouse antibodies [HAMA] and rheumatoid factors) that could react in immunoassays to yield falsely elevated results. This assay minimizes interference from heterophilic antibodies; however, complete elimination cannot be guaranteed.

Limitations

Results should be interpreted in conjunction with the patient's medical history, clinical presentation, and other findings. DVT clinical diagnosis should not be based solely on the Innovance® D-dimer result. D-dimer levels can be elevated due to a variety of clinical conditions, especially in hospitalized patients, and should not be used in pediatric patients for exclusion of venous thrombosis or pulmonary embolism. Several conditions like aortic aneurysm, trauma, surgery, disseminated malignancies, sepsis, and severe infections can increase D-dimer levels.

Test Details

Methodology

Immunoassay (Immunoturbidimetric assay)

Biomarkers

D-Dimer

Analyte

D-Dimer • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

48065-7

Result Codes

48065-7

Result Turnaround Time

1 day

Specimen

Plasma

Volume

2 mL

Minimum Volume

1 mL

Container

Blue-top (sodium citrate) tube

Collection Instructions

Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion for proper blood to anticoagulant ratio. Mix immediately by gentle inversion at least six times. A discard tube is not required before collection. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma, being careful not to disturb the cells. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap and freeze immediately.