Blood Typing Activity

The Patient

You are a lab tech in a hospital. A doctor has a patient who needs a blood transfusion. You have three potential donors. Determine the blood type of the patient and donors. Then, decide who would be an appropriate donor.

Kim is a 43 year old woman who has been in a car crash. She lost a lot of blood through an injury to her leg. Before you can give her a transfusion, you need to determine her blood type. Let’s go down to the lab to walk through the procedure.

In your lab, you have a blood sample and three reagents.

  • a serum with synthetic antibody-A
  • a serum with synthetic antibody-B
  • a serum with synthetic antibody-Rh
A small red bottle labeled blood, a blue bottle labeled antibody-A serum, a yellow bottle labeled antibody-B serum, and a clear bottle labeled antibody-Rh serum,

When the antibody serums are added to a blood sample with the given antigen, they agglutinate, or clump. We can use that knowledge to determine a blood type.

Three wells. In all, there is a light pink liquid with either large irregular or small uniform circular dark red clumps.

See the visible darker red spots and clear areas in the samples above? That’s agglutination.

Start the Test

Start by adding the blood sample to each of the three marked wells in the sample tray.

Open Add Patient Blood Sample in a new tab

Add the antibody-A serum the blood sample in the wells.

Blood well showing blood in A well with light areas and longer dark clots

Do you see agglutination?

Answer: Yes. Since you see agglutination, you know that A antigens are present.

You know that A antigens are present. So, what blood types could our patient have?

Answer: Based on the presence of A antigens, the patient could have A+, A-, AB+, or AB-.

We can narrow the blood type down farther by testing for the B antigen. Add the antibody-B serum to the blood sample.

Blood well showing blood in B well with consistent smooth red color

Do you see agglutination?

Answer: No. Since you do not see agglutination, you know that B antigens are not present.

You know that A antigens are present and B antigens are not present. With this new information, what blood types could our patient have?

Answer: Based on the presence of A antigens and absence of B antigens, we have narrowed the blood types to A+ or A-.

We make our final determination of blood type by testing for the Rh antigen. Add the antibody-Rh serum to the blood sample.

Blood well showing blood in Rh well with clear areas and large patchy clots

Do you see agglutination?

Answer: Yes. Since you see agglutination, you know that Rh antigens are present.

You know that A and Rh antigens are present and B antigens are not present. With this new information, what is our patient’s blood type?

Answer: Since the patient has A and Rh antigens, she has A+ blood. Remember that when you select an appropriate donor.

The Potential Donors

The doctor has three potential donors. Before she can decide on a donor, she needs to know their blood types.

Donor 1

Start by adding the blood sample to each of the three marked wells in the sample tray.

empty blood well with blood samples and serums behind it.

Add all three antibody serums to the tray. Look at the sample. Which antibodies show agglutination?

Blood sample with blood in antibody-A well smooth and uniformly red, in antibody-B blood is pinkish with small circular red clumps, and in antibody-Rh blood has think red flakes with small clear patches.

Answer: The antibody-B and antibody-Rh serum caused agglutination.

You know that B and Rh antigens are present. So, what blood type is our donor?

Answer: Since Donor 1 has B and Rh antibodies, his blood is B+.

Donor 2

Start by adding the blood sample to each of the three marked wells in the sample tray.

empty blood well with blood samples and serums behind it.

Add all three antibody serums to the tray. Look at the sample. Which antibodies show agglutination?

Blood sample with blood in antibody-A showing long stringy clumps in pinkish liquid, in antibody-B blood is pinkish with small circular red clumps, and in antibody-Rh the blood is smooth and uniformly red

Answer: The antibody-A and antibody-B serum caused agglutination.

You know that A and B antigens are present. So, what blood type is our donor?

Answer: Since Donor 2 has A and B antibodies, her blood is AB-.

Donor 3

Start by adding the blood sample to each of the three marked wells in the sample tray.

empty blood well with blood samples and serums behind it.

Add all three antibody serums to the tray. Look at the sample. Which antibodies show agglutination?

Blood sample with blood in antibody-A well that is smooth and uniformly red, in antibody-B blood is smooth and uniformly red, and in antibody-Rh blood has think red flakes with small clear patches.

Answer: The antibody-Rh serum caused agglutination.

You know that Rh antigens are present. So, what blood type is our donor?

Answer: Since Donor 3 has Rh antibodies only, her blood is O+.

Now, we have the blood type for our accident victim (A+) and our three potential donors.

  • Donor 1: B+
  • Donor 2: AB -
  • Donor 3: O+

Based on this information, who is a potential donor for our victim?

Answer: O+ blood is compatible since the patient does not produce any antibodies against this type.

You have successfully identified the blood types of the victim and donors. You have also identified a suitable donor for the victim. Congratulations on saving a life!