Blood Evidence

Delivery of evidence

The evidence collected from the scene should be properly packaged, labeled and sealed before it is delivered to the laboratory for testing. Proper labeling is essential for laboratory applications as well as for court usage. All the items to be submitted to the laboratory should have the name or the names of the suspects or victims, a brief description of the contents of the package, the location the item was collected, the investigator's name and the date and time the items were collected. It is also imperative to place different items in different packages to avoid cross contamination. The packaging containers should be properly selected according to the items to be packaged. Sealing the outer packages of the evidence helps in maintaining the quality of evidence and ensures that the evidence is not tampered with while being delivered to the laboratory. It is also significant to take into consideration safety issues while packaging the evidence. Where the contents of the packages contain items that are likely to be hazardous it is critical to label such packages appropriately to avoid harm.

How to test blood evidence

There are three types of tests that can be conducted on blood evidence. The first test is the conventional serological tests which analyses proteins, antigens and enzymes present in the blood samples. The elements tested here are vulnerable to degradation and requires large samples to obtain ideal results. The other test is the restriction fragment length polymorphism, which analyses the presence of certain DNA sequences in the white blood cells. DNA does not degrade rapidly like proteins and enzymes and, therefore, this procedure is less likely to be affected by degradation. The third type o...

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...arious factors such as the presence of other elements in the samples. These elements do not affect the tests in a similar way and others are more susceptible to these elements than others. The RSID for semen, for instance, is more accurate than the RSID for both blood and saliva since it tests for an antigen that is only specific to the human semen.

Works Cited

Butler, J. M. (2005). Forensic DNA typing: biology, technology, and genetics of STR markers. Academic Press.

Jobling, M. A., & Gill, P. (2004). Encoded evidence: DNA in forensic analysis. Nature Reviews Genetics, 5 (10), 739-751.

Gunn, A. (2008). Essential forensic biology. John Wiley & Sons.

McClintock J. T. (2014). Forensic Analysis of Biological Evidence: A Laboratory Guide for Serological and DNA Typing. CRC Press.

Vince J. J., & Sherlock W. E. (2004). Evidence Collection. Jones & Bartlett Learning.