Blood Typing Lab

STEM Whodunit?Practice Lab

Blood Typing

• What’s your blood type? ex., mine is O+

• ABO and Rh factors are totally independent of each other

 SurfaceAntigens

Antibodies

A A Anti-B

B B Anti-A

AB A, B none

O none Anti-AAnti-B

ABO Antigens and Antibodies

The Rh Factor

• Also called D antigen

• Either Rh positive (Rh+) or Rh negative (Rh-)

 SurfaceAntigens

Rh+ Rh factorRh- none

Blood Type Test • Determines blood type and compatibility

Figure 19–7

Blood Types

• Genetically determined cell surface markers (antigens) on RBCs, including

– ABO group – glycolipids on RBC surface– Rh factor – membrane protein

4 Basic Blood Types• A has surface antigen A• B has surface antigen B• AB has both antigens A and B• O has neither A nor B

• A has type B antibodies• B has type A antibodies• O has both A and B antibodies• AB has neither A nor B antibodies

Figure 19–6a

4 Basic Blood Types

• Antigens also called agglutinogens• Antibodies called agglutinins

Blood type questions

• Which blood type is the best in emergency settings (hint: which type can be given to anyone?)

• Which blood type is the lucky one that can receive blood from any donor?

Cross-Reaction

• If donor and recipient blood types not compatible:

– Plasma antibody meets its specific surface antigen and blood will agglutinate (clot) and hemolyze (kill each other)

– This is really bad….

Figure 19–6b

Cross-Reaction

Blood typing procedures• 6 trays with three wells each

6 Bottles of “blood” 3 Bottles of antibodies

Victim

Suspect 4Suspect 3Suspect 2

Suspect 1Crime scene

AA A

AA ARh BBB

BBB

Rh

Rh Rh Rh

Rh

Blood Typing Procedures• For each well Place 1-2 drops of blood from one

bottle in all 3 wells– 1-2 drops of crime scene in each of the three wells– 1-2 drops of victim in each of the three wells– 1-2 drops of suspect 1 in each of the three wells – 1-2 drops of suspect 2 in each of the three wells – 1-2 drops of suspect 3 in each of the three wells – 1-2 drops of suspect 4 in in each of the three wells

• For each tray add:– 1-3 drops of anti-A serum to one well and stir– 1-3 drops of anti-B serum to one well and stir– 1-3 drops of anti-Rh serum to one well and stirLook for clumping reaction

Blood type?

• What is the blood type? x = clumping rxn.

• Next question: what antibodies does this person have in their blood?

A B Rh

X X

Example of Determining Genotype – Punnett Square

• Mom’s phenotype is group A, genotype AO• Dad’s phenotype is group B, genotype BO

B O

A AB 25% AO 25% (Group A)

O BO 25% (Group B) OO 25% (Group O)

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.