User:Kristinavalle22/Forensic serology

- reword ending statement of starting paragraph to better describe confirmatory tests in lead paragraph


 * "Following the presumptive tests, confirmatory tests are done on the same sample to confirm what the unknown substance actually is"

- For blood detection:

- For sperm detection
 * "...that detects the heme group in blood that transports oxygen and carbon dioxide. (citation)
 * "A sterile cotton swab is soaked in distilled water and applied to the area of suspected blood to pick up some of the sample. One drop of alcohol is applied to the swab, followed by the addition of one drop of the phenolphthalein reagent, followed by one drop of hydrogen peroxide." (info added, reworded and citations)
 * "...where the blood sample is extracted by a wet swab and placed directly on the hemastix. A positive result induces a colour change from yellow to dark green. (reworded and citation)


 * "However, not all males release sperm in their semen. If a male is aspermic or oligospermic, they either have no sperm or a low sperm count. (citation added)

- For saliva detection


 * This detection technique is based on the activity of the enzyme alpha-amylase which breaks down starches from food into smaller oligosaccharide molecules, starting digestion in the mouth (citation added)
 * Using a petri dish gel, the saliva sample is added and allowed to diffuse through the gel overnight. Visualization is accomplished by adding iodine to the gel which stains the starch in the gel blue. If saliva is present, then the alpha-amylase breaks down the starch, creating a clear colored circle around where the sample was placed.
 * Because these tests specifically target amylase, confirmatory tests can not be done considering amylase can be found in other bodily fluids. (completely new sentence, citation added)

SEE BELOW FOR ADDED BODY

Lead
N/A

Blood Detection
Blood is composed of liquid plasma and serum with solid components consisting of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). To detect blood at a crime scene or in the laboratory, an array of tests can be used. The most publicized test by crime shows is the Luminol process in which a chemical is sprayed onto a surface where blood is suspected to be. The chemical reacts with traces of blood, producing a chemi-luminescence, or apparent glow, as a result of the chemical reaction that occurs. As with all presumptive tests, this technique can produce false positive results due to metals and strong chemicals, such as bleach, that will also react. Another common presumptive test is the Kastle-Meyer or Phenolphthalein test. This is a catalytic test that detects the heme group in blood that transports oxygen and carbon dioxide. A sterile cotton swab is soaked in distilled water and applied to the area of suspected blood to pick up some of the sample. One drop of alcohol is applied to the swab, followed by the addition of one drop of the phenolphthalein reagent, followed by one drop of hydrogen peroxide. A positive result induces a color change to pink. Similar to the Kastle-Meyer test, a hemastix is also a catalytic test simplified to a specialized strip where the blood sample is extracted by a wet swab and placed directly on the hemastix. A positive result induces a colour change from yellow to dark green.

Saliva Detection
A presumptive test to detect saliva is the alpha-amylase test also known as the Phadebas Test. This detection technique is based on the activity of the enzyme alpha-amylase which breaks down starches from food into smaller oligosaccharide molecules, starting digestion in the mouth. Using a petri dish gel, the saliva sample is added and allowed to diffuse through the gel overnight. Visualization is accomplished by adding iodine to the gel which stains the starch in the gel blue. If saliva is present, then the alpha-amylase breaks down the starch, creating a clear coloured circle around where the sample was placed. RSID tests have also been made in order to detect alpha-amylase, but they are not always reliable because there can be a lot of false positives.

For confirmatory tests, there has not been as much research done compared to blood and semen. Since these tests specifically target amylase, confirmatory tests can not be done considering amylase can be found in other bodily fluids.

Urine Detection (New)
The presumptive detection of urine can be done by alternative light sources or a paradimethylaminocinnamaldehyde test (DMAC). The DMAC will react with urea, uric acid or ammonia which can all be found in urine. When you have a sample with potential urine, 0.1% DMAC can be applied. If there is a positive reaction, a pink/magenta colour will be present on the stain. There are only presumptive tests for urine detection because the tests used target material that can be found in other bodily fluids. This can cause a lot of false positives and inaccurate results.