The Value Of An Age Adjusted D-dimer Cut-off Value In The Diagnosis Of Acute Pulmonary Embolism

Objective:To evaluate the value of an age adjusted D-dimer cut-off value in the diagnosis of acute pulmonary embolism.Methods:1056patients with suspected pulmonary underwent plasma D-dimer assay by taking spiral CT pulmonary angiography as diagnosis standard. The sensitivity, specificity, accuracy, negative predict value and positive predict value were calculated both the group of traditional standard and the group of the age adjusted cut-off value standard.Results:According to the traditional d-dimer standard, there were352negative cases and704positive cases, including156cases of true positive and343cases of true negative. According to the new d-dimer standard, there were474negative cases and582positive cases, including156cases of true positive and465cases of true negative.The sensitivity, specificity, accuracy, negative predict value and positive predict value of the former were94.55%,38.50%,47.25%,97.44%,22.16%, while which of the later were94.55%,52.19%,58.81%,98.10%,26.80%respectively, there was significant difference between the Youden index of both groups(Z=4.58, P<0.01).Conclusions:Application of the age adjusted D-dimer cut-off value greatly increased the specificity of the D-dimer test for the diagnosis of acute pulmonary embolism among older patients without reducing sensitivity.