blood+detection+outline+thl

Blood detection is separated into three different types - Crystal Tests - not used very much anymore - To see if it is blood, this method is used and makes it crystalize, showing whether not it is blood - The crystals formed are studied under a microscope to see their structure and color - The color is studied after a substance is added to the crystal - common color is pink (Takayama) - These tests are pretty full proof, meaning if positive it almost always guarantees that their is blood, and if it is negative, it still could mean blood

- Catalytic Tests - A test based on color, that can sometimes show if the substance is blood. It is not always reliable because there are other substances that change color in this chemical reaction created as well - Depends on the blood containing the right substance that catalyzes in the reaction with hydrogen peroxide - If it contains this, then a color change can be visible to show if blood is there. - The substance can also become luminescent rather than change color, proved by the Kastle-Meyer test - The method is good for showing whether there is blood or not, but there are many things that can disrupt it like enzymes - The effects of the other factors such as being outside can change the outcome, so it must be noted what was present before believing the results.

- Instrumental Methods - These methods show whether there is hemoglobin or not. Hemoglobin is found in blood, so this test can show for sure if the substance is blood, using chromatography - Using chromatography, it can detect blood, and even age of blood

Using Blood Detection - The color changing methods is used the most, as it is easiest to tell whether the substance is actually blood or not with the color changing ones - Instruments called Sangur sticks can be used to detect color change by rubbing them on the stain, and the Kastle-Meyer method can detect color change as mentioned earlier - Kastle-Meyer technique turns pink after all tests when blood is present after rubbing the stain with paper, and adding reactants to the stain - Neither of the tests really show that there is blood for sure, but they can show that the stain most likely is. It would have to proven that it is human-specific

Blood Detection of Non-Visible Stains - Luminol is used for this, meaning the solution created shows the blood as it illuminates. It is similar to a black light test showing stains, this substance can reproduce the stain where it has been, even it has been partially cleaned up - It does not show just blood, so it is not for sure blood if a stain shows - Blood does not sparkle after being applied with luminol, which can help separate it from other types of stains - You can take pictures of the stains shown by luminol, but it must be enhanced to really see

Enhancing Bloodstains - A whole stain or print of blood is not always shown, so the whole thing can be reproduced using enhancing chemicals that react with blood - A way to enhance the stain is using a violet light that reproduces the rest of the blood stain, after spraying a substance on the stain

Which Methods to Use - when blood needs to be grouped, a lot of the methods can not be used because they ruin the stain after detecting the blood - some of the tests do not show the whole stain, they just show that blood is present, so work on the rest of the stain is still needed - using the DNA poymerase reaction has become popular for blood prints that need to be grouped