Transcript ABO and Rh groups Erythrocytes sedimentation rate

275 BCH
Miss.Tahani Al- Shehri
objective
 To determine the blood group and therefore the type
of antigen carried on the surface of erythrocytes in the
ABO system
 To test the availability of the Rh factor ( D antigen) on
the surface of erythrocytes
 To determine ESR
Introduction & principle
 ABO blood Group system is one of 29 genetically
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independent human blood group system
Each of these system contains a group of structurally
related antigen
These antigens may be proteins, carbohydrates,
glycoproteins, or glycolipids
some of these antigens are also present on the surface of
other types of cells of various tissues and bilogical fluid (
Saliva , milk , seminal fluid urine , ovarian cyst fluid and
gastric fluid ).
All antigens inherited according to mendelian laws of
genetics
Introduction & principle
 Blood group antigens must be determined to
secure a safe practical of blood transfusion.
 They are also useful in determining familial
relationships in forensic medicine .
BIOCHEMISTRY OF THE ABO
SYSTEM
 The ABO antigens are terminal sugars found at the end of long sugar
chains (oligosaccharides) that are attached to lipids on the red cell
membrane.
 The A and B antigens are the last sugar added to the chain. The "O"
antigen is the lack of A or B antigens but it does have the most amount
of next to last terminal sugar that is called the H antigen
 Production of A, B, and H antigens
 The production of A, B and H antigens are controlled by the action of
transferases. These transferases are enzymes that catalyze (or control)
addition of specific sugars to the oligosaccharide chain. The H, A, or B
genes each produce a different transferase, which adds a different
specific sugar to the oligosaccharide chain.
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BIOCHEMISTRY OF THE ABO
SYSTEM
 To understand the process let's look at the sequence of
events:
 Precursor chain of sugars is formed
 N-acetylglucosamine (G1cNAc) and Galactose (Gal).
 H gene causes L-fucose to be added to the terminal
sugar of precursor chain, producing H antigen (shown
in this diagram)
BIOCHEMISTRY OF THE
ABO SYSTEM
 Either A gene causes N-acetylglucosamine (G1cNAc) to be added to
H substance, producing A antigen,
or
 B gene causes D-galactose (Gal). to be added to H substance,
producing B antigen.
 If both A and B genes present, some H-chains converted to A antigen,
some converted to B antigen.
 If H gene absent (extremely rare), no H substance can be formed, and
therefore no A or B antigen. Result is Bombay blood group.
Rh group
Rh group is determined using an
agglutinating IgM anti D
Erythrocytes sedimentation
rate
 Principle
 When anticoagulant blood is allowed to stand, the red
cells settle down due to rouleaux formation to wared
the bottom as the red cells are more dense than
plasma( Sediment under the effect of gravity )
 The rate at which red cells settle down in an hour is
known as Erythrocytes sedimentation rate
Erythrocytes sedimentation
rate
 ESR is used clinically as non-specific screening test to
detect the presence of infection
 It used as well as means of monitoring the status of
chronic inflammatory disease such as rheumatoid
arthritis.
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γ – globin & Fibrinogen
ESR