Latte's crust of blood stain is used to detect -
Ans. is 'c' i.e., Blood groupBlood and blood stainso The examination of blood and blood stains is an important part of crime detection. The points that are usually required to be determined regarding stains are : (1) nature of stain (whether the stains is blood or not); (2) the species (human or animal) from which the blood has come from; and (3) blood group.Nature of stain (whether the stain is blood or not)o To determine the nature of stain, following tests are used :Chemical testsThese tests are based on the peroxidase activity of haematin, which is, derived from oxidation of haem of haemoglobin or methemoglobin, present. This enzyme, in the presence of hydrogen peroxide converts colourless salts into coloured bases. Thus these tests are based on H202 and peroxidase enzyme. Tests are :Benzidine test: Greenish blue colour.Phenolphthalein test (kastle myere test): Deep permanganate colour.Leucomalachite green test: Bluish green or peacock blue colour.Guaiacum test: Blue colour.Orthotoludine test (kohn test): Blue or green colour.Amidopyrine test: Purple colour.Microchemical testsThese tests are based on property of haem part of hemoglobin to form characteristic coloured crystals. The tests are :Teichmann's haemin crystal test.Takayama hemochromogen crystal test.Luminal spray test: It is especially useful in old obscure blood stains.SpetroscopyIt is most delicate and reliable test. It is based on the principle that hemoglobin and its derivatives givecharacteristic absorption bands when viewed through a spectroscope.MicroscopyMicroscopic examination of RBCs is possible only in fresh stains.Detection of species (whether the blood has come from human or animal)o For detection of species, serological (immunological) tests are used. These tests are :Precipitin testHaemaglutination inhibition test (antiglobulin consumption test or absorption inhibition test).Gel diffusion test.Double diffusion test.Precipitation electrophoresis.Latex agglutination test.Isoenzyme method (enzymological test).Detection of blood group of blood staino These tests are :Immunological (serological) : (i) aborption-elution test, (ii) absorption-inhibition test, (iii) mixed agglutinationtest, (iv) latex test.Enzymological methods.Latte fs crust method.
Nature of stain
Detection species
Blood group
None of the above
Biological Materials & Stains