1. Latent Blood
By: Joel Vera

2. kastle-Meyer Test aka the phenolphthalein/peroxidase test - when a blood stain, hydrogen peroxide and phenolphthalein reagent are mixed, the oxidation of the hemoglobin in the blood produces a deep pink color - sensitivity: 1:10,000 (if 1 drop of blood were present in a bucket with 10,000 drops of water, the PHTH test would still turn pink) - Testing Method: swab the stain with a q-tip or some filter paper, add a drop of PHTH, add of drop of peroxide

3. Luminol - also a presumptive test - reaction between blood and luminol produces light instead of color - sensitivity: most sensitive presumptive test - detects bloodstains diluted up to 300,000 times - luminol reagent is sprayed onto items suspected to be blood and the room must be darkened - any blood stains present produce a faint blue glow - advantage: can screen large areas quickly and does not interfere with subsequent DNA testing Reaction: Luminol is C8H7O3N3 - luminol powder is mixed with a liquid containing H2O2 and some other chemicals (H2O2 and luminol are the major players) - the reactions needs a catalyst to accelerate the process - in this case the Fe from hemoglobin is the catalyst - also an oxidation reaction

4. Microcrystalline Tests - 2 common tests: Teichmann Test and Takayama Test - small amount of blood added to microscope slide - chemical solution added - slide heated to form hemoglobin crystals (a pink crystal complex) - crystals can be viewed under a microscope - positive results indicate blood - sensitivity: mL of blood/0.1 mg hemoglobin - 20 year old blood stains have given positive results