#2 - Hematology I Blood Typing

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Ezra Burns
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#2 - Blood Typing Objectives: Learn the theory behind blood typing Be able to perform simulated blood typing and analysis Understand the theory behind blood transfusions (donors and recipients)

Introduction Hematology is the study of the blood and the organs that produce it.

The formed elements in blood include the red blood cells (RBCs) which function to carry oxygen bound to hemoglobin and deliver it to the tissues (Fig. 1). II. Formed Elements (Figure 1) A.

1 #2 - Blood Typing Objectives: Learn the theory behind blood typing Be able to perform simulated blood typing and analysis Understand the theory behind blood transfusions (donors and recipients) Observe a blood smear slide and learn to identify different types of blood cells. Equipment: Remember to bring gloves, goggles, proper shoes & histology atlas. I. Introduction Hematology is the study of the blood and the organs that produce it. Blood is a liquid connective tissue whose matrix is composed of plasma surrounding the formed elements (cells and cell fragments). The formed elements in blood include the red blood cells (RBCs) which function to carry oxygen bound to hemoglobin and deliver it to the tissues (Fig. 1). II. Formed Elements (Figure 1) A. Introduction: The formed elements include: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes) which are cell fragments (Figure 2). There are five types of leukocytes categorized as either granular (containing large visible granules), or agranular (lacking these granules). Granular leukocytes include: neutrophils, basophils, and eosinophils. Agranular leukocytes include: monocytes and lymphocytes (Figure 2). The formed elements of blood can be viewed under the microscope after staining. This slide is called a blood smear. Figure 2. Formed elements in a blood smear slide. Page1

B. Blood Smear Observe the blood smear slide and draw the indicated formed elements viewed under the 40x objective in the laboratory report at the end.

2 B. Blood Smear Observe the blood smear slide and draw the indicated formed elements viewed under the 40x objective in the laboratory report at the end. The easiest leukocytes to find are the neutrophils and lymphocytes since they are in the greatest abundance. Draw the appropriate cells in the lab report and have your microscope checked by your instructor before storage. III. ABO & Rh Blood Grouping Systems A. Introduction: ABO Blood Group The ABO system of blood typing is determined by the presence or absence of specific surface antigens on RBCs. Antigens are molecules that specifically bind to portions of the immune system, and some can cause immune responses. There are many antigens on the surface of RBCs, but the A and B antigens can cause severe immune reactions. When a blood cell has the A antigen on its surface it is typed as A. Similarly if a blood cell has the B antigen on the surface it is typed as B. If neither of the antigens is present the type is O. If both A and B antigens are present on the surface, the type is AB. Rh Blood Group There is another antigen named D, or more commonly Rh antigen, that can be present (Rh+) or absent (Rh-) from the surface of the RBCs. When blood is typed, both the ABO and Rh are described, hence the names of the blood types we are familiar with (for example, B+). A person with this type has both the B and D antigens on the surface of their RBCs. Normally a person does not create antibodies towards the Rh antigen unless they are exposed to it directly for example when a mother who is Rh negative gives birth to a child who is Rh positive. A subsequent child who is Rh positive can then develop hemolytic anemia (erythroblastosis fetalis) Page2

B. Blood Typing Antibodies are proteins that specifically bind antigens. For the blood typing procedure, antibodies that react to the A, B, and D antigens are manufactured in a laboratory.

When the antibodies bind to their specific antigen on the RBC surface, they first cause agglutination of the RBCs.

3 B. Blood Typing Antibodies are proteins that specifically bind antigens. For the blood typing procedure, antibodies that react to the A, B, and D antigens are manufactured in a laboratory. These antibodies are called Anti-A antibodies (they recognize A antigens), Anti-B antibodies (they recognize B antigens), and Anti-D (or Anti-Rh antibodies which recognize the Rh antigen). When the antibodies bind to their specific antigen on the RBC surface, they first cause agglutination of the RBCs. Agglutination is when the cells clump together due to the antibody / antigen interaction. If this occurred in the body, the cells would then undergo hemolysis, where the cell membrane is punctured with holes and the cell dies. For the blood typing procedure, clumping indicates an antibody / antigen reaction and therefore the presence of the A, B or Rh antigen. Follow the procedure for blood typing using the simulated blood (Figure 3). The sample is positive for that antigen if agglutination is present. Agglutination may appear clumpy to just slightly cloudy, especially for the B antigen. It may take a few minutes to see the full reaction. Record your results in the lab report pages and answer the questions. Figure 3. Blood typing experiment. Blood Typing Procedure: 1. Using one clean plastic try, place a few drops of Mr. Smith s blood sample in each well. 2. Place a few drops of anti-serum ie. simulated antibodies in the correct well (anti-a in the well labeled A, anti-b in the well labeled B, and anti-rh in the well labeled Rh). 3. Mix each with a different toothpick to prevent cross contamination of the antibodies. 4. Observe and continue to stir for about 1-2 minutes. 5. Look for a cloudy, crystalline, or clumpy appearance for a positive reaction. 6. Record your results in Table Repeat for the remaining blood samples. 8. You may have to rinse and dry the plastic trays. The fluids may be disposed of down the sink. 9. When you are done, clean and dry the plastic trays DO NOT throw them out! Page3

4 C. Blood Transfusions When blood from one person (the donor) is given to another (the recipient), it is called a transfusion. Only compatible blood types can be transfused from one person to the next. The incompatibility is caused by the reaction of the antibodies in the plasma of the recipient to the antigens on the RBCs of the donor blood. Refer to the diagram below (Figure 4). A person with type A blood has Anti-B antibodies in their plasma. A person with type B blood has Anti-A antibodies in their plasma. Humans form Anti-A and Anti-B antibodies early in life. This is likely due to exposure of similar antigens in our everyday environment. A person does not normally produce antibodies against antigens that are present in their own body. This would cause an immune response. Our own antigens are normally recognized as being self. Therefore a person with A and B antigen (type AB blood) does not have either antibody in their plasma and type O people have both types of antibodies. When a recipient receives blood from an incompatible donor the antibodies in their plasma cause agglutination (sticking together) and hemolysis (bursting/ breaking) of the donated RBCs, which is called a transfusion reaction. Figure 4. Blood agglutinogens (antigens) and antibodies. Therefore, only certain blood types can donate to others. Using the properties of the recipient s antibodies and donor s antigens, determine what individuals can give and receive blood to other types. Put the answers in Table 2 of the lab report. Do not forget that a person can receive from their own blood type as well. Page4

5 Laboratory #2 Report Name: II. A- Blood Smear Draw while viewing under the 40x objective. Erythrocyte Thrombocyte Neutrophil Lymphoctye Monocyte Microscope check: Question: Why were you not asked to draw the eosinophils or the basophils? III. B - Blood typing Table 1. Results of the Blood Typing experiment. Indicate if agglutination was present with each antibody (yes / no) and determine the blood type. Subject Anti-A (yes / no) Anti-B (yes / no) Anti-Rh (yes / no) Determined Blood Type (ex. A+) Mr. Smith Ms. Brown Mr. Green Mr. Jones Page5

6 Definitions: 1. antigen: 2. antibody: 3. agglutination: Question: Why do we use separate toothpicks for each well? C. Blood transfusions Table 2. Indicate which antigens and which antibodies you would expect to be found for each blood type, and then show compatible transfusion blood types. Blood Type A Surface Antigen Plasma Antibody Can Donate To: Can Receive From: B AB O Fill in Circles: Using the information from Table 2, fill in the circles with the appropriate blood types showing how blood can be donated and received (Figure. 5). Questions: 1. Which blood type is the universal donor? Why? 2. Which blood type is the universal recipient? Why? 3. What would happen if someone of type B donated blood to someone with type A blood? Figure 5. Pathways for blood transfusions. Page6

Pearson's Comprehensive Medical Assisting Administrative and Clinical Competencies

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