Blood Compatibility and Plasma Compatibility – What is the Difference?

Blood Compatibility and Plasma Compatibility – What is the Difference?

To understand the compatibility, it is important that we know the bases of ABO blood grouping system. It is based on the presence of specific antigen on red blood cells of an individual.

Table 1 shows the antigens present on red blood cells and antibodies presents in plasma for each blood group.

Table 1. Antigens and Antibodies Present for Each Blood Group

Blood Group Ag Present on RBC ABO Abs Present in Plasma
O No Ag Anti A and anti B
A Ag A Anti B
B Ag B Anti A
AB Ag A and Ag B No Abs
Rh+ Rh D No Abs
Rh- No Ag No Abs

In case of Rh + or Rh– there will be no Abs present naturally in plasma because Rh Abs are developed only after an individual is exposed to Rh D antigen.

Now based on this we can differentiate the compatibility for red blood cell type and plasma type. Keep the above table as reference to understand the compatibility.

During transfusion it is preferable for a patient to receive blood and plasma of the same ABO and RhD group but if the required type is not available based on compatibility they may be given alternative type as shown in table 2.

Table 2. Blood Compatibility and Plasma Compatibility for Each Blood Group

Recipient Blood Type Donor RBC Donor Whole Blood

(RBC + Plasma)

Donor Plasma
A+ A+, A-, O+, O- A+ A- A+, A-, AB+, AB-
A- A-, O- A- A+, A-, AB+, AB-
B+ B+, B-, O+, O- B+, B- B+, B-, AB+, AB-
B- B-, O- B- B+, B-, AB+, AB-
O+ O+, O- O+, O- A+, A-, B+, B-, O+, O-, AB+, AB-
O- O- O- A+, A-, B+, B-, O+, O-, AB+, AB-
AB+ A+, A-, B+, B-, O+, O-, AB+, AB- AB+, AB- AB+, AB-
AB- AB-, A-, B-, O- AB- AB+, AB-

When it comes to blood transfusion, it can be either only red cells or blood as a whole. So if we are talking about RBC, we need to consider only Ags from donor but when we are talking about whole blood since it has both RBC and plasma we need to consider both Ags and Abs from donor. In case of plasma we need to consider only Abs from donor because plasma doesn’t have RBC and so no Ags.

As shown in table 2, plasma from blood group AB can be given to blood group O. But when it comes to blood as a whole because of present of Ags on RBC, O type cannot accept red blood cells or blood as whole from any other blood type other than blood group O.

Blood group A and B type individuals can accept plasma from AB individuals because blood group AB type will not have any Abs in their plasma.

Blood group AB type can accept plasma from only AB type because it is the only plasma without anti A and anti B Abs in it.

Rh- individual can accept plasma from Rh+ individual because there are no anti Rh antibodies present naturally in plasma.

In blood transfusion and to be specific for red cell transfusion, AB is universal acceptor and O is universal donor.

But in plasma transfusion, AB is universal donor and O is universal acceptor.

I hope this helps 🙂

Watch a video on this topic here.

Antigen vs Pathogen – What is the Difference?

Antigen vs Pathogen – What is the Difference?

  • Pathogen –

We all might have experienced falling sick such as having fever or infection. In very simple term if I put it, the organism which has the ability to make us sick is called pathogen. An organism that can cause disease is called pathogen. Pathogens can be bacteria, viruses, fungi and even protozoa. Pathogens are foreign organisms which mean they are different than bacteria found in our body or on our skin (normal flora). Normal flora is friendly bacteria but pathogens are not, pathogens invade our body and cause disease.

When pathogen enters our body we would expect our immune system to fight against it. But do you know that our immune system or immune cells cannot recognize pathogen as whole. What they can recognize is a specific part (molecule) of a pathogen present on its surface. These specific molecules present on surface of pathogen and recognized by immune system is called antigen. 

  • Antigen – Antibody generator

Antigen means Antibody generator. It is a molecule located on the cell wall of bacteria or on coat of virus or on any other organism. Antigens are generally proteins but they can also be polysaccharides, nucleic acid or lipids.

These antigens present on pathogens are very specific for that particular pathogen. Such as an Ag present on Mycobacterium tuberculosis is unique to it and is different than an Ag present on Salmonella.

One more important thing to know about Ag is that the term Ag is not restricted to these surface molecules only. An Ag can be any foreign molecule which triggers immune response in our body. Such as MHC molecule from a different individual in organ transplant, some protein in food, component of serum etc.

So the major difference over here that we need to understand is Pathogen is a whole organism which causes the disease but Ag is part of this organism which is actually recognized by our immune system. 

Figure – Difference between Antigen and Pathogen

I hope this post helps 🙂

To understand more details, watch a video on this topic here.