Read the following passage carefully before proceeding.
Blood typing is one of the most important discoveries in the history of medicine. Before Austrian physician Karl Landsteiner identified the ABO blood group system in 1901, blood transfusions were often fatal because doctors did not understand why some patients died after receiving donated blood. Today, blood typing saves millions of lives every year by ensuring compatible blood is used in transfusions, surgeries, and organ transplants.
Blood is made up of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). The surface of every red blood cell is covered with proteins and sugar molecules called antigens. The ABO blood group system classifies blood based on which antigens are present on the surface of the red blood cells. There are two main antigens — Type A and Type B — which gives us four possible blood types: Type A (has A antigens), Type B (has B antigens), Type AB (has both A and B antigens), and Type O (has no A or B antigens).
The immune system produces proteins called antibodies that recognize and attack foreign antigens. A person with Type A blood has anti-B antibodies in their plasma; a person with Type B blood has anti-A antibodies. Type O blood has both anti-A and anti-B antibodies, while Type AB blood has neither. When incompatible blood is transfused, the recipient's antibodies attack the donor's red blood cells, causing them to clump together in a process called agglutination. Agglutination can block blood vessels and trigger a life-threatening immune response.
In addition to the ABO system, blood is classified by the Rh factor, also called the D antigen. If the D antigen is present on red blood cells, the person is Rh-positive (Rh+); if absent, they are Rh-negative (Rh–). About 85% of people are Rh-positive. The Rh factor is especially critical during pregnancy. If an Rh-negative mother carries an Rh-positive fetus, the mother's immune system can produce antibodies against the baby's blood — a condition called hemolytic disease of the newborn (HDN). This is why Rh-negative pregnant women are given a medication called Rh immunoglobulin (RhoGAM) to prevent antibody formation.
Blood typing is performed by mixing a blood sample with specific antibody solutions called antisera. Anti-A serum contains antibodies against the A antigen, and anti-B serum contains antibodies against the B antigen. If agglutination (clumping) occurs when anti-A serum is added, the blood contains A antigens (and is therefore Type A or AB). A similar test is done with anti-B serum and anti-D serum for the Rh factor. Medical professionals must always verify a patient's blood type before any transfusion or surgery to prevent potentially fatal reactions.
Because Type O-negative blood contains no A, B, or Rh antigens, it can be given to any patient regardless of blood type. This makes O-negative donors "universal donors." Conversely, Type AB-positive individuals can receive any blood type and are called "universal recipients." Understanding blood compatibility is a cornerstone of modern medicine and is essential knowledge for anyone entering the biomedical field.
Use information from the reading to complete the following.
1. Complete the following statement using information from the reading passage:
2. Rearrange the words below to form a correct scientific statement about the Rh factor:
3. Explain in your own words why a person with Type O-negative blood is called a "universal donor." Use at least TWO pieces of scientific evidence from the reading in your response.
4. Rearrange the words to form a correct statement about ABO blood types and antibodies:
Answer all 5 questions based on the reading passage. Score: 1 point each.
Click each card to flip it and read the definition. Hold for 20 seconds, then it flips back. Study all cards before the matching activity!
Click a term on the left, then click its correct definition on the right.
5 questions, 1 point each.
Read this guide carefully before beginning the simulation.
In a clinical laboratory, blood typing is performed using a process called agglutination testing. A small sample of a patient's blood is placed into separate wells on a testing slide or tile. Each well receives a different antiserum — a solution containing specific antibodies. The three antisera used are:
When an antiserum is added to blood, one of two things happens: agglutination (clumping) or no reaction. If the antigen matching that antiserum is present on the red blood cells, the antibodies in the serum will bind to those antigens, causing the cells to clump together visibly — this is a positive reaction (+). If the antigen is NOT present, the blood remains smooth and uniform — a negative reaction (−).
By reading the results of all three wells together, a technician can determine a patient's complete blood type, including the ABO group and Rh factor.
Example Patient: "Patient X"
| Blood Type | Anti-A Serum | Anti-B Serum | Anti-D Serum | Antigens Present |
|---|---|---|---|---|
| A+ | + (Clump) | − (None) | + (Clump) | A, Rh |
| A− | + (Clump) | − (None) | − (None) | A only |
| B+ | − (None) | + (Clump) | + (Clump) | B, Rh |
| B− | − (None) | + (Clump) | − (None) | B only |
| AB+ | + (Clump) | + (Clump) | + (Clump) | A, B, Rh |
| AB− | + (Clump) | + (Clump) | − (None) | A, B only |
| O+ | − (None) | − (None) | + (Clump) | Rh only |
| O− | − (None) | − (None) | − (None) | None (Universal Donor) |
Now it's your turn! Use the simulation below to determine blood types.
Select a mystery blood type below, then click each Add Antiserum button to test all three wells. Observe the reaction in each petri dish, then record your results in the data table.
Complete the table below by testing all 8 blood types. Record "+" for agglutination and "−" for no reaction.
| Blood Type | Anti-A Serum | Anti-B Serum | Anti-D Serum (Rh) | Your Conclusion |
|---|
Use the compatibility matrix below to answer the analysis questions.
| Recipient ↓ / Donor → | O− | O+ | A− | A+ | B− | B+ | AB− | AB+ |
|---|
1. Based on the compatibility matrix, which blood type(s) can a person with Type AB+ receive? Explain why.
2. A patient with Type A− needs an emergency transfusion and no A− blood is available. Which other blood type(s) could safely be used? Use evidence from the matrix to support your answer.
3. Why is Rh-negative blood preferred in emergency situations when a patient's blood type is unknown?
5 questions, 1 point each.
Read each case carefully and answer the constructed response questions that follow.
Case 1 – Question A: Which blood type should the medical team use, and why? Use scientific terminology in your answer.
Case 1 – Question B: Complete the statement below:
Case 2 – Question A: Explain the biological mechanism by which Maria's Rh-negative status could cause harm to this or a future fetus. Use the terms antigen, antibody, and immune response in your answer.
Case 2 – Question B: Rearrange the words to form the correct scientific statement about this situation:
Case 3 – Question A: Evaluate each patient and determine who can safely receive the B+ kidney. Justify your answer using compatibility principles.
Case 3 – Question B: Complete the statement:
Case 4 – Question A: Explain on a molecular level why James experienced a transfusion reaction. Include the role of antigens, antibodies, and agglutination in your response.
Case 4 – Question B: Rearrange the words to form a statement describing what occurred in James's bloodstream:
5 questions, 1 point each.
| Section | Points Earned | Points Possible | % |
|---|
Click the button below to open the print dialog. Choose "Save as PDF" to save a copy of your completed lab.
Tip: In the print dialog, select "Save as PDF" as the destination.