D-dimer testing: A narrative review.

D-dimer containing species are soluble fibrin degradation products derived from plasmin-mediated degradation of cross-linked fibrin, i.e., 'D-dimer'. D-dimer can hence be considered a biomarker of in vivo activation of both coagulation and fibrinolysis, the leading clinical application in daily practice of which is ruling out venous thromboembolism (VTE). D-dimer has been further evaluated for assessing the risk of VTE recurrence and helping define optimal duration of anticoagulation treatment in VTE, for diagnosing disseminated intravascular coagulation (DIC), and for screening those at enhanced risk of VTE. D-dimer assays should however be performed as intended by regulatory agencies, as their use outside these indications might make them a laboratory-developed test (LDT). This narrative review is aimed at: (1) reviewing the definition of D-dimer, (2) discussing preanalytical variables affecting D-dimer measurement, (3) reviewing and comparing the assays performance and some postanalytical variables (e.g., different units and age-adjusted cutoffs), and (4) discussing the interest of D-dimer measurement across different clinical settings, including pregnancy, cancer, and coronavirus disease 2019 (COVID-19).

Pre-admission anticoagulant therapy and mortality in hospitalized COVID-19 patients: A covid predict retrospectivecohort study

Background : A high incidence of venous thromboembolism (VTE) is observed in patients with COVID-19. Furthermore, several studies show that hypercoagulability is associated with mortality. Aims : To investigate whether pre-admission anticoagulant therapy is associated with a lower risk of all-cause mortality in hospitalized COVID-19 patients. Methods : Retrospective data from 1,851 consecutive patients with PCR-confirmed SARS-CoV-2 infection hospitalized in eight Dutch centres between February 27 th and August 1 st 2020 were used. During this period, Dutch guidelines recommended routine thromboprophylaxis for all hospitalized COVID-19 patients. After 1:1 propensity score nearest-neighbour matching based on age, sex, and 17 comorbidities, the association between pre-admission anticoagulant therapy for VTE, atrial fibrillation, or other indications (i.e. direct oral anticoagulants or vitamin K antagonists) and all-cause mortality and intensive care unit (ICU) admission was evaluated. A secondary analysis was performed with a broader definition of antithrombotic therapy including anticoagulants and antiplatelet drugs. Results : Mean age was 66.4 years (SD, 14.8) and 39% were women. Pre-admission, 678 patients (37%) were using anticoagulant and/or antiplatelet therapy of whom 287 (16%) used anticoagulant therapy only, 408 (22%) antiplatelet therapy only, and 17 both anticoagulant and antiplatelet therapy. 253 anticoagulant users and 253 patients not using therapeutic anticoagulation were matched. During a median follow-up of 21 days [IQR: 9.8-21.0], anticoagulant therapy was neither associated with all-cause mortality (hazard ratio [HR], 0.95;95%-CI, 0.70-1.27;Figure 1) nor with ICU admission (HR, 1.0;95%-CI, 0.59-1.70). Results did not materially change in the secondary analysis of anticoagulant and/or antiplatelet therapy (HR for mortality, 1.18 [95%-CI, 0.87-1.59] and HR for ICU admission, 2.98 [95%-CI, 0.60-1.39]). Conclusions : In this retrospective cohort study, pre-admission anticoagulant use was not associated with a lower risk of mortality or ICU admission in hospitalized COVID-19 patients. Further data from randomized controlled trials are needed to determine the riskbenefit ratio of initiating anticoagulant therapy during admission for COVID-19.