Exclusion of venous thromboembolism: evaluation of D-Dimer PLUS for the quantitative determination of D-dimer.
ABSTRACT The objective of this study was to evaluate if D-Dimer PLUS (Dade Behring, USA), a rapid fully automated assay, could be used as an initial screening test in the diagnosis of venous thromboembolism (VTE). Samples from 274 consecutive symptomatic patients with suspected pulmonary embolism (n=229; 79% outpatients, 21% inpatients), deep venous thrombosis (n=37; 84% outpatients, 16% inpatients) or suspected for both complications (n=8) were tested with this D-dimer assay with a Sysmex CA-1500 Coagulation Analyzer. Clinical probability for pulmonary embolism (PE) or deep venous thrombosis (DVT) was staged according to a pretest risk score proposed by Wells. Final diagnosis of PE and/or DVT was established by spiral-computed tomography of the pulmonary arteries or compression ultrasonography, respectively. PE was diagnosed in 13.5% of the patients, whereas DVT was confirmed in 17.7% of the patients. The optimal cut-off value for exclusion of venous thromboembolism was 130 mug/l, and sensitivity, specificity and negative predictive value (NPV) were 95.0% (95% CI: 92.4-97.6), 30.4% (95% CI: 25.0-35.8) and 97.2% (95% CI: 95.2-99.2), respectively. In fact, two patient with PE were missed using D-Dimer PLUS; both cases were outpatients. In conclusion, this assay appears to be safe when implemented in an algorithm based on clinical assessment, D-dimer concentration, and radiological diagnostic techniques to stratify the risk for PE or DVT. However, higher sensitivities and negative predictive values were claimed in the scarce published reports for the D-Dimer PLUS assay than found in this study.
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ABSTRACT: The new england journal of medicine 1247 clinical practice This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the authors' clinical recommendations. An otherwise healthy 51-year-old woman presents to her physician with pleuritic right posterior chest pain, without dyspnea or hemoptysis. Her temperature is 38.2°C, and her pulse is 102 beats per minute. Physical examination discloses a pleural fric-tion rub over the posterior right hemithorax but is otherwise unremarkable. A chest radiograph is normal. She is treated with an antiinflammatory agent for presumed viral pleurisy. Three days later, she returns, reporting dyspnea. How should she be evaluated? Although the exact incidence of pulmonary embolism is uncertain, it is estimated that 600,000 episodes occur each year in the United States, resulting in 100,000 to 200,000 deaths. 1 When the diagnosis of embolism is confirmed and effective therapy is initiat-ed, recurrence of embolism is rare and death is uncommon — with the exception of pa-tients who initially present with hemodynamic impairment, among whom the mortal-ity rate approaches 20 to 30 percent. 2,3 The majority of preventable deaths associated with pulmonary embolism can be ascribed to a missed diagnosis rather than to a failure of existing therapies. The diagnosis of pulmonary embolism is confounded by a clinical presentation that may be subtle, atypical, or obscured by another coexisting disease. 4 Several noninva-sive diagnostic techniques have been developed to improve the accuracy of diagnosis and limit the number of patients who require angiography, a procedure that is associ-ated with some risk and is underutilized in traditional diagnostic strategies. 5,6 Howev-er, no single noninvasive diagnostic test is sufficiently sensitive or specific for the diag-nosis in all patients.New England Journal of Medicine 10/2003; 349(13):1247-56. · 51.66 Impact Factor
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ABSTRACT: Our objective was to evaluate, in a routine clinical setting, the role of spiral CT as a second procedure in patients with clinically suspected pulmonary embolism (PE) and abnormal perfusion scan. We prospectively studied the role of spiral CT in 279 patients suspected of PE. All patients started their diagnostic algorithm with chest radiographs and perfusion scintigraphy. Depending on the results of perfusion scintigraphy, patients proceeded to subsequent levels in the algorithm: stop if perfusion scintigraphy was normal; CT and pulmonary angiography if subsegmental perfusion defects were seen; ventilation scintigraphy followed by CT when segmental perfusion defects were seen; and pulmonary angiography in this last group when results of ventilation/perfusion scintigraphy and CT were incongruent. Reference diagnosis was based on normal perfusion scintigraphy, high probability perfusion/ventilation scintigraphy in combination with abnormal CT, or pulmonary angiography. If PE was present, the largest involved branch was noted on pulmonary angiography, or on spiral CT scan in case of a high-probability ventilation/perfusion scan and a positive CT scan. A distinction was made between embolism in a segmental branch or larger, or subsegmental embolism. Two hundred seventy-nine patients had abnormal scintigraphy. In 27 patients spiral CT and/or pulmonary angiography were non-diagnostic and these were excluded for image analysis. Using spiral CT we correctly identified 117 of 135 patients with PE, and 106 of 117 patients without PE. Sensitivity and specificity was therefore 87 and 91%, respectively. Prevalence of PE was 53%. Positive and negative predictive values were, respectively, 91 and 86%. In the high-probability group, sensitivity and specificity increased to 97 and 100%, respectively, with a prevalence of 90%. In the non-high probability-group sensitivity and specificity decreased to 61 and 89%, respectively, with a prevalence of 25%. In a routine clinical setting single-detector spiral CT technology has limited value as a second diagnostic test because of low added value in patients with a high-probability lung scan and low sensitivity in patients with non-high-probability lung scan result.European Radiology 08/2003; 13(7):1501-7. · 3.55 Impact Factor
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ABSTRACT: The performances for thromboembolic disease exclusion of a new microlatex-enhanced D-dimer immunoassay have been evaluated. Advanced D-dimer (Dade-Behring, Marburg, Germany) was tested with two automated analyzers, namely BCS and CA-1500. Precision studies yielded coefficients of variation (within-run and run-to-run) of 3% and 6.3% at D-dimer levels near the cut-off value, for BCS and CA-1500 respectively. Frozen samples from 294 consecutive symptomatic outpatients suspected of either deep venous thrombosis (140) or pulmonary embolism (154) from a previous management study were tested with both analyzers, as well as with the VIDAS New assay (BioMerieux, Marcy-l'Etoile, France). For BCS, sensitivity and specificity were 96.6% (95% CI, 90.5, 99.3) and 42% (35.1, 49.0) respectively at a cut-off value of 1.35 microg/ml. For CA-1500, the corresponding figures were 95.5% (88.9, 98.8) and 47.8% (40.8, 54.9) at a cutt-off value of 1.1 microg/ml. This assay appears promising and should be validated in clinical practise to assess its place in the work-up schemes of thromboembolism.Thrombosis Research 10/2002; 107(5):197-200. · 3.13 Impact Factor