Blood Grouping, Serum and Plasma By Elkhedir Elgorashi, MLT, M Sc
Blood Grouping • Blood group antigens are actually sugars attached to the red blood cell. • Antigens are “built” onto the red cell.
Antibody Clinical Significance • Immunizations are frequently done to protect us from disease. • Receive Hepatitis B immunization. • Actual bits of hepatitis virus injected. • Body recognizes as foreign and produces an immune antibody. • Subsequent exposure to real Hepatitis B virus will result in destruction of the virus by immune antibodies. • ABO antibodies are immune and will result in destroying incompatible cells which may result in the death of the recipient.
Group O • Approximately 45% of the population is group O. • No A or B antigens present, think of as “0” antigens present. • These individuals form potent anti-A and anti-B antibodies which circulate in the blood plasma at all times.
Group A • Approximately 40% of the population is group A. • No B antigens present. • These individuals form potent anti-B antibodies which circulate in the blood plasma at all times
Group B • Approximately 11% of the population is group B. • No A antigens present. • These individuals form potent anti-A antibodies which circulate in the blood plasma at all times.
Group AB • Approximately 4% of the population is group AB. • Both A and B antigens present. • These individuals possess no ABO antibodies. • NOTE: This slide is in error as it only illustrates presence of one antigen not 2.
Rh (D) Antigen • Of next importance is the Rh type. • Term “Rh” is a misnomer. • Rh is a blood group system with many antigens, one of which is D. • Re-education of public is difficult. • Rh refers to the presence or absence of the D antigen on the red blood cell.
Rh (D) Antigen (continued) • Unlike the ABO blood group system, individuals who lack the D antigen do not naturally make it. • Production of antibody to D requires exposure to the antigen. • The D antigen is very immunogenic, i.e, individuals exposed to it will very likely make an antibody to it. • For this reason all individuals are typed for D, if negative must receive Rh (D) negative blood.
Rh (D) Antigen (continued) • The most important patient population to consider is females of child-bearing age. • If immunized to Rh (D) antigen the antibody can cross the placenta and destroy Rh (D) positive fetal cells resulting in death. • This is why Rh negative women are given Rhogam after birth of Rh positive baby.
Blood Typing • There are 2 components to blood typing: • Test unknown cells with known antibodies • Test unknown serum/plasma with known RBCs • The patterns are compared and the blood group is determined.
Slide Blood Typing • Very rudimentary method for determining blood groups. • CANNOT be used for transfusion purposes as false positives and negatives do occur. • A “false positive” is when agglutination occurs not because the antigen is present, but cells may already be clumped. • A “false negative” is one in which the cells are not clumped because there are too many cells or not enough reagent.
Slide Blood Typing - continued • The slide is divided into halves. • On one side a drop of anti-A is added, this will attach to and cause clumping of RBCs possessing the A antigen. • On the other side a drop of anti-B is added which will cause clumping of RBCs with the B antigen. • A drop of RBCs is added to each side and mixed well with the reagent. • The slide is tilted back and forth for one minute and observed for agglutination (clumping) of the RBCs
Interpretation of Slide TypingTesting with Anti-A Anti-Serum • If an RBCs contains the A antigen the red blood cells will be agglutinated by anti-A, a positive reaction. • If an RBCs does not have the A antigen there will be no clumping, a negative reaction.
Interpretation of Slide TypingTesting with Anti-B Anti-Serum • If an RBCs contains the B antigen the red blood cells will be agglutinated by anti-B, a positive reaction. • If an RBCs does not have the B antigen there will be no clumping by anti-B, a negative reaction.
Slide Blood Typing Group A • An unknown RBCs suspension is added to known anti-sera. • The left hand of the slide contains anti-A which reacts with the unknown cell. • The right hand side contains anti-B which does not react with the cell.
Slide Blood Typing Group B • An unknown RBCs suspension is added to known anti-sera. • The left hand of the slide contains anti-A does not react with the unknown cell. • The right hand side contains anti-B which reacts with the cell.
Slide Blood Typing Group O • The left hand of the slide contains anti-A does not react with the unknown cell. • The right hand side contains anti-B does not react with the unknown cell.
Slide Blood Typing Group AB • The left hand of the slide contains anti-A which reacts with the unknown cell. • The right hand side contains anti-B which reacts with the unknown cell.
Material Requirement Antisera Blood container Wooden Sticks Syringes Slides Centrifuge
Blood Sample • Capillary Blood or Venous Blood
Agglutination as a bear Clumping
Serum and Plasma Serum and plasma
Sample Venous Blood only
Plasma • Blood plasmais the liquid component of blood. Plasma itself is around 90% water, with the 10% remainder including proteins, minerals, waste products, clotting factors, hormones, and immunoglobins. Plasma also performs a number of other useful functions in the body.
Plasma (continued) • Separating blood plasma from the blood itself is very easy. Blood can be drawn from the patient and then run in a centrifuge. As the blood spins, the heavier blood cells settle to the bottom, and the plasma rises to the top. • Plasma is usually straw colored, although it can be cloudy or grayish.
Plasma (continued) • Blood plasma flows constantly, and the components of plasma are constantly being renewed. In addition to providing nutrition and waste cleanup, blood plasma also harbors immune system cells which attack infections in the body, and it is used to deliver hormones and clotting factors to areas where they are needed.
Plasma Preparation Material Required Blood container(Violate cap) Gloves Syringes Centrifuge
Serum • Is the component that is neither a blood cell (serum does not contain white or red blood cells) nor a clotting factor; it is the blood plasma with the fibrinogens removed. Serum includes all proteins not used in blood clotting (coagulation) and all the electrolytes, antibodies, antigens, hormones, and any exogenous substances (e.g., drugs and microorganisms).
Serum (continued) • The study of serum is serology. Serum is used in numerous diagnostic tests, as well as in blood typing. • Serum is an essential factor for the self-renewal of embryonic stem cells in combination with the cytokine leukemia inhibitory factor.
Preparation of Serum • Blood is centrifuged to remove cellular components. Anti-coagulated blood yields plasma containing fibrinogen and clotting factors. Coagulated blood (clotted blood) yields serum without fibrinogen, although some clotting factors remain.
Material Required Blood container (Red cap) Gloves Syringes Centrifuge