Blood Groups
Patients with blood group AB are less likely to be affected
What our notes say
- Patients with blood group AB are less likely to be affected (Internal Medicine 4th Year 1st Semester CAT: HIV and the gut, liver disease and )
- Splenomegaly is a later effect, but the blood groups are the key. (Paediatrics main exam (MBPE 4300): 24 January 2022, Paper One, 100 MCQs, 2 short)
- UTI pathogenesis: P-fimbriae (P-pili) are the virulence factor associated with ability to cause urinary tract infection, specifically in patients with the P blood group antigen (fimbriae bind to a receptor related to this blood group) (Streptococcus Classification, S. pyogenes, Rheumatic Fever, AGN)
- Laboratory tests: haemoglobin, blood group and Rhesus, HIV, VDRL or syphilis, urinalysis, malaria and hepatitis B where indicated. (Reproductive Health 1 End of Trimester CAT: ectopic pregnancy, ANC and abortion )
- Resuscitate: IV access, fluids, blood group and crossmatch, transfuse if shocked. (Reproductive Health 1 End of Trimester CAT: ectopic pregnancy, ANC and abortion )
- Haemoglobin and full blood count, random blood glucose, urea, electrolytes and creatinine, liver function, blood group and cross-match, and a HIV test. (Junior Clerkship in Reproductive Health (MBOG 4200): end of year examination, 4 )
Study material on Blood Groups
- Blood Transfusion: ABO, Rh Blood Groups, Compatibility & HDN
- Transfusion: Governance, Donor Selection & Blood Groups
- Blood Grouping and Blood Typing
- Blood Transfusion Medicine: An Exam-Focused Review
- Master Blood Transfusion: A Medical Quiz on Reactions & Tests
- Paediatrics main exam (MBPE 4300): 24 January 2022, Paper One, 100 MCQs, 2 short essays and 2 long essays
- Medical Bacteriology and Entomology
- Medical Bacteriology and Entomology MCQs
- Molecular Biology Exam Review MCQs
- Blood Transfusion — Past Paper Questions & Answers
Practice questions on Blood Groups
Which blood group system is most frequently associated with delayed hemolytic transfusion reactions that present with a rapid drop in hemoglobin but negative initial antibody screens?
- Kell
- Duffy
- Kidd
- MNS
Answer: C. The Kidd system is the classic cause of delayed hemolytic transfusion reactions. Antibodies fade quickly, screen negative, then surge after re-exposure causing rapid intravascular hemolysis. ---
A 23-year-old woman with recurrent UTIs, at least one episode of pyelonephritis. Blood typing shows the P blood group antigen. Likely primary cause of her infections
- Escherichia coli producing heat-stable toxin
- Escherichia coli with K1 (capsular type 1) antigen
- Escherichia coli O139 (LPS O antigen 139)
- Escherichia coli with P-pili (fimbriae)
- Escherichia coli O157:H7 (LPS O antigen 157; flagellar antigen H7) Answer:
Answer: A. P-pili (fimbriae) bind to a receptor related to the P blood group antigen on uroepithelial cells, mediating attachment and ascending infection to the kidneys (pyelonephritis). --- ---
Which blood group system is most frequently associated with delayed hemolytic transfusion reactions that present with a rapid drop in hemoglobin but negative initial antibody screens?
- Kell
- Duffy
- MNS
- Kidd
Answer: D. > The Kidd system is the classic cause of delayed hemolytic transfusion reactions. Antibodies fade quickly, screen negative, then surge after re-exposure causing rapid intravascular hemolysis. ---
Most important blood group system after ABO and Rh?
- Kell
- Duffy
- Kidd
- MNS
Answer: A. Kell antigens are highly immunogenic and clinically the next most significant after ABO and Rh. ---
A patient experiences an unexpected drop in haemoglobin and mild jaundice approximately 7 days after receiving a blood transfusion. A direct antiglobulin test (DAT) is positive. Which blood group system is most notoriously associated with this type of reaction?
- The ABO blood group system due to common pre-formed IgM antibodies.
- The Rh blood group system, often involving anti-D following Rh-positive exposure.
- The Duffy blood group system, known for its association with malaria resistance.
- The Kidd blood group system, notorious for causing anamnestic antibody responses.
Answer: D. The timing (3-10 days post-transfusion), fall in Hb, mild jaundice, and positive DAT are consistent with a delayed haemolytic transfusion reaction (DHTR). DHTRs occur when low-level alloantibodies, often not detected on initial antibody screens, are boosted by the transfused RBCs, leading to an anamnestic immune response. The Kidd blood group system is particularly notorious for causing these types of reactions, as K
Which ABO blood group is known as the 'universal donor' for red cell transfusion?
- A, A
- B, B
- AB
- O
- Rh-negative ✅ Answer: C
Answer: A. While O negative is the universal donor for red cells, the provided answer sheet indicates AB.