Click here for more information about laboratory operations and procedures
|Performed by||Parnassus Hematology|
|In House Availability||24 hours, 7 days per week|
|Collection Instructions||Blue top filled to full extent of vacuum
|Container type||3.2% sodium citrate, Blue top tube
|Amount to Collect||2.7 mL|
|Sample type||Citrated plasma|
|Preferred volume||1.0 mL plasma|
|Min. Volume||0.5 mL plasma|
|Processing notes||Deliver specimen immediately to Hematology
|Normal range||<400 ng/mL|
|Synonyms||FDD; Fibrin D-Dimers|
|Stability||Room temperature 4 hours|
|Turn around times||1 hour|
|Additional information||Evaluation of Pulmonary Embolism for Outpatients Presenting to the Emergency Department: in settings for which the clinical suspicion of pulmonary embolism is such that imaging of the chest may be performed (helical contrast CT or V/Q scan), a FDD <400 ng/mL may permit imaging to be avoided. Clinical correlation is advised. The FDD should only be ordered when there is substantive clinical suspicion for PE because elevated D-dimers is a non-specific finding. In fact, approximately 10% of healthy blood donors may have D-dimers > 400 ng/mL (UCSF in-house studies, 2004 and 2009).
There are a number of settings in which D-Dimers should not be used to exclude thromboembolic disease. Among these settings are: children, patients with high probability for thromboemoblic disease by clinical criteria, patients on anticoagulation therapy, patients with suspected thrombus distal to the knee, and patients with suspected upper extremity venous thrombosis. In addition, D-dimers may be cleared from the circulation following thrombosis (approximately half-life 7 hours) so D-dimer testing may be of limited value in patients for whom substantial time has elapsed between onset of thrombosis and laboratory testing. (Reference: Clinical Laboratory Standard Institute Document H59-P Quantitative D-Dimer for the Exclusion of Venous Thromboembolic Disease; Proposed Guideline)
Evaluation of Disseminated Intravascular Coagulation: obtain a current PT, PTT, Platelet Count and Fibrinogen before ordering FDD. Serial studies following the demonstration of a positive result are not useful, nor is this test generally appropriate if the other test parameters are stable and within normal limits.
The assay will be run if no FDD has been run in 48 hours, or if FDD was run between 24-48 hours with a result of <6000 ng/mL. If specimen does not meet these criteria and the test is cancelled, contact Hematology Lab Medicine Resident at X31747 if clinical condition warrants immediate re-evaluation of FDD level.
Cloudy specimens (e.g. lipemia) may yield artifactually low values. In some cases, such specimens cannot yield interpretable results.
The presence of rheumatoid factor at a level greater than 50 IU/mL may lead to an over-estimation of the D-Dimer level.
|Last Updated||5/15/2013 2:29:32 PM|
If you have additional questions regarding this test, please call: 415-353-1667