Latte's crust of blood stain is used to detect

NEET PG
#1

Latte’s crust of blood stain is used to
detect ?
a) Nature of stain
b) Detection species
c) Blood group
d) None of the above
Correct Answer - C
Ans. is ‘c’ i.e., Blood group
Blood and blood stains
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)
To determine the nature of stain, following tests are used :

  1. Chemical tests
  2. These 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 :
  3. Benzidine test: Greenish blue colour.
  4. Phenolphthalein test (kastle myere test) : Deep permanganate
    colour.
  5. Leucomalachite green test : Bluish green or peacock blue colour.
  6. Guaiacum test : Blue colour.
    rthotoludine test (kohn test) : Blue or green colour.
  7. Amidopyrine test : Purple colour.
  8. Microchemical tests
    These tests are based on property of haem part of hemoglobin to
    form characteristic coloured crystals. The tests are :
  9. Teichmann’s haemin crystal test.
  10. Takayama hemochromogen crystal test.
  11. Luminal spray test : It is especially useful in old obscure blood
    stains.
  12. Spetroscopy
    It is most delicate and reliable test. It is based on the principle that
    hemoglobin and its derivatives give characteristic absorption bands
    when viewed through a spectroscope.
  13. Microscopy
    Microscopic examination of RBCs is possible only in fresh stains.
    Detection of species (whether the blood has come from human
    or animal)
    For detection of species, serological (immunological) tests are used.
    These tests are :
  14. Precipitin test
  15. Haemaglutination inhibition test (antiglobulin consumption test or
    absorption inhibition test).
  16. Gel diffusion test.
  17. Double diffusion test.
  18. Precipitation electrophoresis.
  19. Latex agglutination test.
  20. Isoenzyme method (enzymological test).
    Detection of blood group of blood stain
    These tests are :
  21. Immunological (serological) : (i) aborption-elution test, (ii)
    absorption-inhibition test, (iii) mixed agglutination test, (iv) latex test.
  22. Enzymological methods.
  23. Latte’s crust method.