An efficient extraction method from blood clots for studies requiring both host and viral DNA

The clot from blood is usually discarded after the collection of serum. Yet, it contains nucleated white blood cells and substantial serum. Here, we have compared four methods to enable quick and efficient extraction of human genomic and viral DNA from clotted blood. Two of these methods, a phenol-based in-house method and Tripure isolation reagent, only achieved a low polymerase chain reaction (PCR) yield. In contrast, the QIAamp blood kit and the High Pure Viral Nucleic Acid kit were equally efficient, with similar sensitivity to serum for extraction of viral DNA.