The assay of D-dimer is claimed to have value in excluding the diagnosis of Deep Vein Thrombosis (DVT); Enzyme-Linked Immunosorbent Assay (ELISA) techniques snowed a very high sensitivity and negative predictive value in the diagnosis of DVT, but are not suitable for emergency. New rapid methods are available which are suitable for extensive use in critically ill patients with suspected DVT, but few clinical trials have assessed their performance in this setting. The diagnostic accuracy of D-dimer assay is mainly related to the technique used (latex or ELISA), but other variables may be important such as thrombus extension, duration of symptoms or concomitant heparin treatment. In order to evaluate the conditions affecting the accuracy of D-dimer, we investigated 131 patients suspected of DVT and 74 suspected of Greater Saphenous Vein (GSV) thrombosis referred to our Emergency Department (ED). All patients underwent compression ultrasonography of the lower limbs and blood sample for semi-quantitative latex D-dimer assay (Dimertest(r), Dade Behring) were taken. Venous thrombosis was confirmed in 38 out of 131 patients with suspected DVT (29%) and in 36 out of 74 (48.6%) patients suspected of GSV thrombosis. The diagnostic accuracy of Dimertest(r), is reported in the table. Our results show that concomitant heparin administration, non-acute symptoms and superficial thrombosis, reduce the accuracy of the test as the rate of false negative results is increased. All patients Excluded patients Excluded patients Patients clinically on heparin with symptoms suspected of dating> 15days GSV thrombosis Sensitivity (95% 81.5% (69.1-93.9) 88.5% (78.5-98.5) 91.1%(81.5-100.7) 74% (57.9-90.5) Confidence Intervals) Specificity 78.4% (70-86.8) 78.4% (70-86.8) 78.4% (70-86.8) 89.4% (79.5-99.3) Positive 60.7% (47.3-74.1) 60.7%(47.3-74.1) 60.7%(47.3-74.1) 83.3% (68.1-98.5) Predictive Value Negative 91.2% (85-97.4) 94.8% (89.5-100.1) 96% (91.6-100.4) 82.9% (71.5-94.3) Predictive Value.
|Issue number||11 PART II|
|Publication status||Published - 2000|
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