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Unformatted text preview: Jason Lim Serology Lab Write Up October 19, 2010 Blood evidence is documented through the use of photography, video and crime scene sketches. With recent technology, there are computer programs that can sketch crime scenes and the user is able to input blood spatter points to calculate points of origins. Blood evidence collection varies depending on the state of the blood. All blood evidence should be labeled with the collector's initials along with a date and time, and also a description of the evidence. The method of collecting blood varies based on the blood's condition. For wet blood, the evidence can be collected by cotton swabs or other absorbent materials. The item used to extract the blood is then placed in an open tube for it to air-dry. Wet samples should not be collected in air-tight containers since it degrades faster than if it is air-dried; if sealed in a container, the sample must be delivered in less than two hours. Refrigeration also keeps the sample intact until it reaches the lab. Dry blood is easier to collect than wet blood. If possible, the blood can be scraped off with a scalpel or knife and collected into a paper packet. If an object is stained with blood, then it is best to send the object itself to the lab instead of gathering blood off of it. If sending the entire blood stained object is not an option, then investigators cut a smaller portion off to test. When investigators suspect that the crime scene was cleaned up, luminol is a solution to reveal the hidden blood. Luminol reacts with any iron, so it reacts with the invisible blood's hemoglobin. If any blood is revealed, the investigator will photograph and record where it is at. Visible blood is preferred over hidden blood, as luminol can dilute or even ruin the blood as evidence. Such solutions are a last attempt to find blood....
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This note was uploaded on 04/25/2011 for the course SOC 261 taught by Professor Barbaraweekley during the Fall '10 term at Saint Louis.
- Fall '10