Guidelines of the National Heart, Lung, and Blood Institute Working Group on Blood Drawing, Processing, and Storage for Genetic Studies.

The guidelines presented here are intended for epidemiologic investigators who wish to store blood samples for genetic studies, either by extracting DNA directly from white blood cells or from immortalized cell lines. Recommended procedures for blood drawing and for processing samples are described. Protocols for freezing and storage of both white blood cells and extracted DNA are provided. Although the extraction of DNA and immortalization of cell lines should be conducted in collaboration with an experienced laboratory, a summary of the available methods with appropriate references is given, and a method for the extraction of DNA from clotted blood is referenced. In addition, criteria for selecting study subjects for whom immortalized cell lines are preferable to merely extracting DNA are presented. Finally, the use of alternative sources of genetic material, including cheek swabs and dried blood spots, is described briefly.