A prospective study of plasma DNA in the diagnosis of pulmonary embolism.

To assess the usefulness of plasma deoxyribonucleic acid (DNA) detection in the diagnosis of pulmonary embolism (PE), we prospectively studied the frequency and duration of the occurrence of free plasma DNA in 23 patients with PE and in 49 patients with pneumonia, myocardial infarction, thrombophlebitis, or normal lung scans. Plasma DNA was detected in 19 of the 23 patients (83 per cent) with PE and in none of the 49 patients with other diagnoses. Eighteen of the 19 PE patients with free DNA had persistence of DNA on all subsequent sampling for up to 5 days. In this series, plasma DNA had a sensitivity of 83 per cent in the diagnosis of PE and was extremely specific for PE. Thus, detection of free plasma DNA may be useful as a rapid, noninvasive test to aid in the diagnois of PE.