Figure 1.

Experimental workflow. A, Plasma specimens were collected from a clinical population including healthy individuals, patients with risk factors for cardiovascular disease, and patients diagnosed with acute stroke. Sample sizes and basic demographic information are indicated; each male or female figure represents 4 individuals of that sex (numbers rounded nearest value divisible by 4) and error is presented as standard deviation. B, Plasma specimens were spiked with equimolar amounts of a nonhuman 605-base pair green fluorescence protein DNA fragment (GFP₆₀₅) generated from the green fluorescence protein (GFP)-encoding loci of the pGFP-v-RS plasmid. C, Total DNA was extracted from spiked plasma specimens via fully automated solid phase anion exchange. D, Spike-in recovery was assessed via quantitative polymerase chain reaction targeting a 108-base pair internal fragment (GFP₁₀₈) and used to calculate DNA extraction efficiencies.