How is Blood Evidence used in Forensics

1. How is Blood Evidence used in Forensics? Provide information about how blood evidence is collected, categorized and compared. How do scientists determine if a fluid is blood? Are those tests foolproof?

2. How blood evidence is collected Blood pool �collect with gauze pad or clear cotton. Let air dry and refrigerate of freeze within 48 hours. Dried blood �wrap object in clean paper and place in paper bag. Small object, send whole object in. Large object, cover with paper and tape down or scrape it off with a knife.

3. How blood evidence is categorized and compared Bloodtypes- A, B, AB, or O Antiserum A or Antiserum B to determine type Rh factor is most commonly know antigen but there are over 256. Dried blood- Heat sample to break antibody antigen bonds Add know blood group to see what coagulates.

4. How scientist determine if a fluid is blood Use Luminol to determine if blood is present, but once luminol is used it destroys the blood for further testing. Takes 5 second to read. Luminol cause blood to glow. Dried blood Takayama and Teichmann -crystallization test Kastle-meyer � chemical phenophthalein turns it pink if there is evidence of blood. Precipitin determines if it is animal or human blood

5. Foolproof? No Other substances may react with chemical used Blood degrades Evidence of Chimerism Secretors

6. Websites used Collection and Preservation of Blood Evidence from Crime Scenes, by George Schiro, Forensic scientist Louisiana State police Crime Laboratory; http://www.crime-scene-investigator.net/blood.html http://www.crimelibrary.com/criminal_mind/forensics/serology/four.html http://nobelprize.org/educational_games/medicine/landsteiner/readmore.html http://www.faculty.ncwc.edu/TOCONNOR/425/425lect13.htm