DNA Purification from Bloodstains and Buccal Cells/Saliva on FTA^® Cards

FTA^® cards enable efficient, long-term storage of blood and buccal cells/saliva samples for future forensic DNA analysis; these are typically collected as known reference samples, as opposed to evidentiary, crime scene samples. Upon contact with the FTA^® card, cells are lysed and the DNA is immobilized. Different FTA^® cards are available and have been specially formulated based on sample type: bloodstains are added to the traditional FTA^® Card, while colorless sources (e.g., buccal cells/saliva) are added to the FTA^® Indicating Card. The main difference between these cards is the presence of a pink dye embedded in the indicating cards that becomes white when exposed to colorless fluids, like saliva; this aids in location confirmation of the stain for future sampling. Although DNA can be eluted/extracted from FTA^® punches using various methods or, alternatively, direct STR amplification from unpurified punches can be performed, the protocol herein describes a simple purification method for bloodstained punches from FTA^® Cards as well as buccal/saliva-stained punches from FTA^® Indicating Cards. Following this purification, STR amplification can be performed via the "punch-in" method.