Blood Typing Lab

Jehan Schemmel Anatomy/6 January 27, 2013 ABO and RH Blood Typing Lab Introduction: The fact that there were four different kinds of human blood, A, B, AB, and O, was discovered around 1900 by Karl Landsteiner. Blood type was found to be determined by presence or absence of antigens, A and B, on red blood cells. Antibodies form against the antigens present in an individual’s blood; blood type A has anti-B antibodies and A antigens, blood type AB has neither antibodies and A and B antigens, blood type B has anti-A antibodies and B antigens, and blood type O has neither A nor B antigens and both anti-A and anti-B antibodies. This process of antibody formation begins shortly after birth and is thought to be started by bacteria entering the body. This experiment was conducted to determine blood type using and developing skills for observation of agglutination reactions with samples of actual blood.

Materials and Methods: Materials needed were 2 sterile alcohol pads, 1 sterile lancet, 1 blood typing tray, 3 toothpicks, gloves, goggles, apron, Anti-A typing serum, Anti-B typing serum, Anti-Rh typing serum, and a biohazard bag. Precautionary and sanitary measures were to be taken before conducting the experiment. After cleaning the tips of fingers, a sterile lancet package was to be opened and used to prick the finger. The sterile lancet was then to be disposed of in a biohazard bag. A drop of blood from the pricked finger was to be added to each well of the blood typing tray and finger tips were to be cleansed again. After disposing of the sterile alcohol pad, a drop of Anti-A serum was added to the A well of the tray, Anti-B serum added to the B well, and Anti-Rh serum added to the Rh well. Using 3 individual clean toothpicks, each

well was to be stirred and disposed of afterwards. Examination for agglutination was then done and blood type was determined. Individual and class results were recorded afterwards.

Data:

Blood Sample

Blood Type

Anti-A Serum

Anti-B Serum

Anti-Rh Serum

Blood Type

No

Yes

Yes

B+

# of Students with

Total # in Class

Blood Type

% of Students with Blood type

A

2

15

13%

B

5

33%

AB

5

33%

O

3

20%

After observing agglutination, individual data showed agglutination present in the B well and Rh well, indicating a blood type of B+. Class data was not representative of the entire population, given the small total number of students in this experiment. AB and B were the most common in the class data, both showing 33%, as opposed to the US population percentages of 4% and 12% respectively. The other blood types were skewed as well in the class sample, with A and O respectively yielding percentages of 13% and 20%, as opposed to population parameters of 45% and 29%.

Discussion: This experiment was easy to make errors in because agglutination was harder to decipher in the Rh and B wells. Because of this, the class data, as well as the individual data, may have been skewed. Actual blood types may have differed from the blood types obtained in the experiment due to the dicey observations. While there is not much that could have been done to improve this experiment in this way, using a magnifying glass or other magnifying object may have helped with deciphering agglutination in some of the wells. After this experiment and reading of the background, questions arose over whether blood type affects ability to ward off infections and bacteria, as well as whether certain blood types are more common in different races and why. For individual data with a B+ blood type, Anti-A agglutinins and B agglutinogens can be found in this blood type. B+ blood can receive B and O blood and could donate to B and AB blood types. Blood typing is a useful tool that can be used at crime scenes, blood donations, and paternity testing. In paternity testing, blood types can be used when proving whether a man could or could not have fathered a child given his and the baby’s blood type. For example, a woman of blood type A accusing a man of blood type B of fathering her blood type O child, blood typing could be used. One would figure that blood types B and O could not have produced a blood type A baby because there are no A antigens present in either the man or the mother’s blood. Therefore, the man could not biologically be the father. To minimize the risks when dealing with blood and blood typing, one should sterilize the equipment used, use sterile equipment, sterilize hands, wear gloves, and dispose of material contacted with blood properly in a biohazard bag. Another benefit of blood typing is in the field of crime scene investigation. A crime scene investigator must know blood types in many cases. He must be able to distinguish different types of blood and match it with a crime scene in order to rule out or prove possible

guilt for potential criminals. By knowing blood types, he can make out identities of those involved in a crime scene. Blood typing is essential for this career.

IA

IB

IB

IAIB

IBIB

i

IAi

IBi

In this case, blood type AB has a 25% chance of occurring, blood type A a 25% chance, blood type B a 50% chance, and blood type O a 0% chance.

Conclusion: The experiment was meant to show the actual process of blood typing and agglutination in a controlled setting. The results, although not representative of the entire population or potentially not totally accurate, of the class were observed as well.