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D-dimer versus FDP

From Anne Gaffney: Hi George, we would like to discontinue our fibrin degradation products (FDP, fibrin split products, FSP) latex agglutination testing, however the OB docs like to use the less sensitive test as the D-dimer test is “always” positive in their pregnant patients.  Do you have any evidence based literature to help us support our discontinuation of this test? Have there been any studies in regards to a D-dimer “cut-off” for r/o of VTE in the pregnant patient?  Thanks for any insight you may have!

Hello, Anne, and thank you for this provocative question. I’ve sent it to several of our regular contributors for assistance, which I anticipate will arrive soon. The key answer to your question is, we can use the quantitative D-dimer assay to rule out venous thromboembolism in patients with low pre-test probability, but not the FDP, which is designed only to identify and monitor the extreme elevations associated with DIC. Unfortunately, because the D-dimer assay is sensitive to inflammation, it rises in pregancy, active malignancy, or nearly any chronic disorder. Thus it may not be useful in ruling out VTE in these conditions. Since VTE is a common occurrance in pregnancy, I’m hoping some of our contributors can help with an approach that can make the assay useful. Meanwhile, here is a citation for an excellent review of the D-dimer assay:

Olson JD. D-dimer: An overview of hemostasis and fibrinolysis, assays, and clinical applications. Adv Clin Chem. 2015;69:1–46

Comments (1)
Sep 11, 2017 5:11pm

Establishing new cutoff for 5
Establishing new cutoff for D-dimer assays for DVT in pregnancy: Chan WS, Lee A, Spencer FA, Chunilal S, Crowther M, Wu W, Johnston M, Rodger M, Ginsberg JS. D-dimer testing in pregnant patients: towards determining the next ‘level’ in the diagnosis of deep vein thrombosis. J Thromb Haemost. 2010; 8:1004–11.

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