Performance of the Quantitative Latex Immunoturbidimetric D-dimer Assay for the Diagnosis of Acute Pulmonary Embolism at Rafik Hariri University Hospital

Background and aims: The diagnostic workup for pulmonary embolism (PE) includes D-dimer assay and computed tomographic angiography. Several Ddimer assays have been approved for PE diagnosis with different sensitivity and specificity. We aimed to study the sensitivity and specificity of the quantitative latex agglutination D-dimer assay used in a referral teaching hospital in Lebanon for the diagnosis of acute PE. Methods: Using a retrospective chart review, we studied 300 patients who had D-dimer test at Rafik Hariri University Hospital in the period between January 1, 2012 and December 31, 2013. Accordingly, 93 patients had a CT angiography after being suspected to have acute PE. A statistical table 2*2 was used to compare the results of CT angiography and Ddimer test. Results: Thirteen patients (13.97%) had PE and 60 patients (64.51%) had positive Ddimer test. Quantitative latex agglutination Ddimer assay had a sensitivity of 69%, specificity of 36%, and negative predictive value of 88%. False positive ratio was also 64%. Moreover, the receiver operating characteristic (ROC) curve was obtained with an area under the curve measuring 0.527. Conclusion: Quantitative latex agglutination D-dimer assay has a high negative predictive value; thus, it can exclude a PE diagnosis if it is associated with low clinical pretest probability.