Question

A person meets with an accident and great loss of blood has occurred. There is no time to analyse his blood group. It is safe to transfer the blood group of
A. AB, Rh +
B. AB, Rh –
C. O, Rh +
D. O, Rh

Answer 1

Blood is a special type of connective tissue that consists of elements like RBC, WBC platelets, plasma, and fluid matrix to stop. It is the transport material of the body. The color and texture of the blood are similar in every human being but they differ in certain factors among humans. Based on the presence and absence of such factors ABO grouping and RH grouping are done.

Complete answer:
● ABO blood grouping is done based on the presence or absence of certain antigens and
antibodies in the blood.
● Antigens are chemicals that produce an immune response against any foreign bodies entering
our system.
● Antigens are seen on the surface of RBC. Mostly 2 antigens are seen on the RBC surface namely
A and B. In some people, both reasons may be present. In some of the two are present and in
others, neither of the two will be present.
● Antibodies are proteins that are produced in response to the antigens. Antibodies are present in
the plasma of blood.
● Antibodies formed against antigen A is called anti-A and antibodies formed against antigen B is
called anti -B.
● Four types of blood groups are commonly seen in human beings- A, B, AB, and O.
● The presence of antigen and antibodies in the four blood groups are shown below:

Blood group	Ag on RBC	Ab on plasma	Donor group
A	A	Anti B	A, O
B	B	Anti A	B, O
AB	A, B	Nil	A,B,AB,O
O	Nil	Anti A, Anti B	O

● From the above table, it is clear that the blood group that can be given to a person whose blood group is unknown is the O blood group. People with O blood group are called Universal Donors.
● RH grouping is done on the basis of the presence or absence of an RH antigen that was first isolated from Macaca rhesus. In the majority of humans ( approximately 80% )RH antigen is present such individuals are called RH positive and people who lack RH antigen are negative.
● If a person lacking RH antigen is given RH positive blood antibodies will be formed against RH antigen therefore it is preferred to transfer negative blood to A person with an unknown blood group.

Therefore, the blood group that is preferred transfer to the patient is O negative blood group, so, option (D) is correct.

Note:
If the person receiving the blood is having a blood group A, blood group B or AB blood group their RBC surface will contain antigen A, B, and AB respectively. The antibodies present in the O blood group that are anti-A and anti-B will cross-react with the patient’s blood and may cause coagulation of blood. But as the amount of blood transfusion is of a very small amount the coagulation will not have a great impact on the patient’s body. So it is preferable to choose the same blood group for transfusion.