Free plasma DNA in patients with pulmonary embolism

Plasma samples from 46 patients with suspected pulmonary embolism and 25 patients with suspected acute myocardial infarction were analyzed for DNA by counterimmunoelectrophoresis (CIE). Anti-DNA serum was obtained from a patient with systemic lupus erythematosus who had a high titer of anti-DNA antibodies. Seven of eight patients (88%) with high probability of pulmonary embolism by lung scan criteria had free DNA in their plasma. Six of 21 patients (29%) with low probability scans for pulmonary embolism also had DNA in their plasma. None of the eight patients with normal scans and only one of 13 patients with myocardial infarction had DNA in their plasma. Detection of plasma DNA by CIE is a rapid and simple method of screening for pulmonary embolism.