Latte's crust of blood stain is used to detect

Blood groups ABO, MNS and Rh are determined in a blood stain by (1) Latte&;s crust method. (2) Absorption- elution technique. (3) Absorption-inhibition. (4) Latex method. (5) Enzymological methods. TESTS FOR DETERMINING ABO GROUPING IN BLOOD STAINS : (1) TUBE METHOD : A drop of washed suspension of red cells is added to equal volumes of each of the antisera of A, B and 0 in separate tubes. The blood group can be identified when agglutination is seen by naked eye or microscope in the tubes. (2) Tile Method: A porcelian tile is used instead of tubes. (3) ABSORPTION -INHIBITION METHOD : The sample and antisera are allowed to react with each other for a longer period. ( 4) MIXED AGGLUTINATION TEST : The sample piece of stained cloth is cut into pieces of 2 to 3 mm and the fibres are separated and added to tubes along with antisera of A, B, 0 types. The group can be known by the antisera which clumped to the cloth fibres. (5) ABSORPTION-ELUTION TECHNIQUE: Test is similar to mixed agglutination, but the clumps are seen on the walls of the test tube and not on fibres. This test can be used for body tissues also. Blood stains can be typed for the presence of ABO agglutinogens by absorption-elution, absorption- inhibition, mixed agglutination or ELISA method, or for agglutinins by the Lattes crust method. Ref:- k s narayan reddy; pg num:-453,454