What does a Kastle-Meyer blood test do?
The 3-stage Kastle–Meyer (KM) test has been used for decades as a rapid, presumptive test for blood. The test identifies the heme component of hemoglobin, which in the presence of hydrogen peroxide catalyzes the oxidation of the indicator phenolophthalin, turning it pink [1], [2].
What does a positive Kastle-Meyer test result?
If the swab turns pink rapidly, it is said to test presumptive positive for blood. Waiting for periods over 30 seconds will result in most swabs turning pink naturally as they oxidize on their own in the air.
What is the principle of Kastle-Meyer test?
The Kastle-Meyer solution is a phenolphthalein indication solution which has been reduced, usually by reacting it with powdered zinc. The basis of the test is that the peroxidase-like activity of the hemoglobin in blood catalyzes the oxidation of the colorless reduced phenolphthalein into bright pink phenolphthalein.
What is Kastle-Meyer reagent?
Kastle–Meyer reagent contains reduced phenolphthalein indicator in a basic solution. Simply wipe a presumptive bloodstain with a cotton swab, add a drop of the reagent, and then apply a drop of hydrogen peroxide. If the swab turns pink rapidly, it is positive for blood!
What is the Kastle-Meyer test quizlet?
The Kastle-Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. If there is blood present, a dark pink color is produced.
What does the phenolphthalein test indicate?
The phenolphthalein test (also known as the Kastle-Meyer test) is a presumptive test for the presence of hemoglobin, a component of the red blood cells in blood.
How does phenolphthalein work for blood?
Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color. While bloodstains normally appear red-brown in color, the color of the substrate or the age of a stain may affect the appearance or visibility of the stain.
What is LMG blood test?
The Leucomalachite green test (LMG test) is another presumptive test used for the detection of blood13. This reaction is also catal- ysed by haemoglobin and a green colour is produced. Hydrogen peroxide acts as an oxidizer in this reaction and the reaction is carried out in an acetic acid medium.
What is Kastle-Meyer made of?
Procedure. In a test tube, dissolve 0.1 g phenolphthalein in 10.0 ml of 25% sodium hydroxide solution. Add 0.1 g mossy zinc to the tube. The solution should be bright pink.
What chemicals are used in the Kastle-Meyer test quizlet?
Name in order of chemicals used in the Kastle-Meyer test. Distilled water, ethyl alcohol, phenolphthalein, hydrogen peroxide.
Is luminol an element?
Luminol is an organic compound which, when oxidized, emits light — a phenomenon known as chemiluminescence.
How does luminol reveal a bloodstain?
Luminol is often combined with hydrogen peroxide to react with the heme groups in blood, producing a bright blue glow, known as chemiluminescence. This glow allows crime scene technicians to detect blood that has dried on surfaces or to detect blood that someone tried to clean from a surface.