Blood type

What is Blood Typing?
Blood typing is a method to tell what type of blood you have so you can safely donate your blood or receive a
blood transfusion. It is also done to see if you have a substance called Rh factor on the surface of your red
blood cells (Erythroblastosis Fetalis).

Your blood type is based on whether or not certain proteins are on your red blood cells. These proteins are
called antigens. Your blood type (or blood group) depends on what types your parents passed down to you.

Blood is often grouped according to the ABO blood typing system and Rh system. The 4 major blood types
are:

• Type A (Antigen A + Antibody B)

• Type B (Antigen B + Antibody A)

• Type AB (Antigen A and Antigen B + No Antibodies

• Type O (No Antigens + Antibody A and Antibody B)

How the Blood Typing Test is Performed?
A blood sample is needed. The test to determine your blood group is called ABO typing. Your blood sample is
mixed with antibodies against type A and B blood. Then, the sample is checked to see whether or not the blood
cells stick together or react (agglutination). If blood cells stick together or react, it means the blood reacted
with one of the antibodies. The type of antibodies that the RBC reacts with will determine the type of blood.
For example, if the unknown blood sample reacts with Anti-serum B( which contains antibody-B) then the
unknown blood sample is Type B. If the unknown blood sample reacts with Anti-serum A (which has
antibody – A) then the unknown sample is Type A. If the unknown sample does not react with either Anti- A
or Anti-B serum then the unknown blood sample is Type O.

Rh typing uses a method similar to ABO typing. When blood typing is done to see if you have Rh factor on the
surface of your red blood cells, the results will be one of these:

• Rh+ (positive), if you have the Rh protein

• Rh- (negative), if you do not have the Rh protein

What is a Transfusion Reaction?
If the blood types do not match then that is called Transfusion Reaction.

• Your immune system will see the donated red blood cells as foreign.

• Antibodies will develop against the donated red blood cells and attack these blood cells.

The two ways that your blood and the donated blood may not match are:

• A mismatch between blood types A, B, AB, and O. This is the most common form of a mismatch. In most
cases, the immune response is very severe.

• Rh factor may not match.

Blood typing is very important during pregnancy. Careful testing can prevent a severe anemia in the
newborn and jaundice (which is referred to as HDN i.e. Hemolytic Disease of the Newborn or Erythroblastosis
Fetalis).

How the Blood Typing Test Results are read and understood?
• You will be told which ABO blood type you have. It will be one of these: A, B, AB, O
• You will also be told whether you have Rh-positive blood or Rh-negative blood.
• Based on your results, your health care providers can determine which type of blood you can safely

receive:
 If you have type A blood, you can only receive types A and O blood.
 If you have type B blood, you can only receive types B and O blood.
 If you have type AB blood, you can receive types A, B, AB, and O blood. (Blood

Type AB+ve is Universal recipient because it has no antibodies)
 If you have type O blood, you can only receive type O blood.(Blood Type O-ve is

Universal Donor because it has no antigens)
 If you are Rh+, you can receive both Rh+ or Rh- blood.
 If you are Rh-, you can only receive Rh- blood.

 Based on your results you can also figure out who you can donate your blood too.

 O: Type O individuals can donate blood to anyone, because their blood has no antigens.

 A: Type A individuals can donate to other type A individuals and type AB individuals.

 B: Type B individuals can donate blood to other B individuals and AB individuals.

 AB: Type AB individuals can donate blood only to other AB individuals

 Rh+: Individuals who are Rh+ can only donate to other Rh+ individuals

 Rh-: Individuals who are Rh- can donate to Rh+ and Rh- individuals

What is Cross-matching?
There are many antigens besides the major ones (A, B, and Rh). Many minor ones are not routinely detected
during blood typing. If they are not detected, you may still have a reaction when receiving certain types of
blood, even if the A, B, and Rh antigens are matched.

A process called cross-matching followed by a Coombs test can help detect these minor antigens. It is done
before transfusions, except in emergency situations.

BLOOD TYPING STUDENT ACTIVITY (Please watch the videos below to
understand how blood typing test is done)

A Generic Video on How Blood Typing is done

A Generic Blood Typing Activity

Note: Antigens for Rh are commonly referred to as Antigen D.

No reaction

Reaction

Blood Typing Case-Study Scenario
You are working in a hospital emergency room on a graveyard shift. Four patients are brought in by the EMTs
who have been in a horrific car accident. They all have wounds and have lost lot of blood. The ER doctor says
that each one of them requires a blood transfusion right away. The blood bank at the hospital is running low.
There is only one pint of blood remaining for each of A+, AB–, B–, and O+ blood types, and no blood of any
other type in stock.

No Reaction

Reaction

Patient 1

Identify this Blood Group

Reaction

No Reaction

Patient 2

Identify this Blood Group

Patient 3

Anti-Rh

No reaction

Identify this Blood Group

Reaction

Anti-B

Anti-A

Patient 4

Anti-Rh

No Reaction

Reaction

Identify this Blood Group

Anti-B

Anti-A

Results:
(Charts A and B Must be included on the Results Section of your Lab Report)

Chart A Reaction with anti-A Reaction with anti-B Reaction with anti-Rh

Patient 1

Patient 2

Patient 3

Patient 4

(Must be included in the Results Section of your Lab Report)

Chart B What is the
patient’s

blood type?

What blood types can
the patient safely
receive?

Which of the only four available pints of
blood (A+, AB–, B–, and O+) should the

patient receive for a transfusion?

Patient 1

Patient 2

Patient 3

Patient 4

Chart C (Reference)

Blood type Reaction with

anti-A
Reaction with

anti-B
Reaction with

anti-Rh

Can receive blood from

A– agglutination none none A– and O–

A+ agglutination none agglutination A+, A–, O+, and O–

B– none agglutination none B– and O–

B+ none agglutination agglutination B+, B–, O+, and O–

AB– agglutination agglutination none A–, B–, AB–, and O–

AB+ agglutination agglutination agglutination any blood type

O– none none none only O–

O+ none none agglutination O+ and O–

Discussion Questions: While you are working in groups, please answer the following questions.

Make sure to justify your answers.

All answers must be in a paragraph format and included in the Discussion Section of your Lab

Report.

1) Identify the blood groups of the following four accident patients who were brought in by the EMTs.

2) Is there a universal donor among the 4 patients who can donate blood to the other car accident patients, if
the Hospital Blood Bank does not have their blood types?

3) Is any one of the accident patients, a universal recipient type who can receive blood from any individual if
the Hospital Blood Bank runs out on blood?

4) What Antibodies are present in Patient # 2. Please mentions both types ie Rh and ABO

5) What Antigens are present in Patient # 3. Please mentions both types ie Rh and ABO

6) Who can patient # 1 donate to?

7) Who can patient # 4 receive from?

8) How can you determine a person’s blood type using blood-clotting tests?

Credits

Hennager, D. J. (2010). Blood Types. Blood Types. Cedar Rapids, IA: Kirkwood Community

College.

Gordon Betts, J., Young, K. A., Wise, J. A., Johnson, E., Poe, B., Kruse, D., Oksana, K.,

Johnson, J.E., Womble, M., DeSaix, P. (2013). 18.6 Blood Typing. In Anatomy and

Physiology. Houston, TX: OpenStax. Retrieved from