Red Blood Cell
Also written as RBC.
The ratio of Red blood cells to White blood cells in the body is:
What our notes say
- The ratio of Red blood cells to White blood cells in the body is: (cat 2 2014 — Source Paper Awaiting Edit)
- HIV 1 measuring 120 nm which is about 60 times smaller than a red blood cell (Physio Y1 EOY 2021 — Past Paper Questions & Answers)
- • Respiratory - red blood cells (erythrocytes) transport oxygen to tissue cells and carbon dioxide is transported by blood to the lungs foe elimination (Cardiovascular system examination revised 2012 — Past Paper Questions & Answers)
- This is made possible by the red blood cells which contain haemoglobin (Examination of Respiratory system — Past Paper Questions & Answers)
- The urine dipstick test for blood is positive but no red blood cells are seen on microscopic examination of the urine sediment. (renal pathology — Past Paper Questions & Answers)
- Red blood cell casts, 2+ protein, pyuria and red cells too numerous to count (Paediatrics end of 3rd trimester exam (MBPE 4300): 11 January 2022, congenital h)
Study material on Red Blood Cell
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- Clinical Chemistry CAT 1 — Blood Transfusion
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- Weekly Year 2: Cellular Immunology Exam - June 12, 2026 (Section A: MCQs)
- Weekly Year 2: Cellular Immunology Exam - June 5, 2026 (Section A: MCQs)
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Practice questions on Red Blood Cell
A 22-year-old woman has a congenital anemia. She has required multiple transfusions of red blood cells for many years. She now has a darker bronze colour to her skin on physical examination. Which of the following microscopic findings would most likely present in her liver?
- Steatosis in hepatocytes
- Bilirubin in canaliculi
- Hemosiderin in hepatocytes
- Glycogen in hepatocytes
- Amyloid in portal triads
Answer: C. There is 250 mg of iron in each unit of blood. The body has no mechanism for getting rid of excess iron. A small amount of iron is lost with normal desquamation of epithelia, and menstruating women will lose a bit more. The excess iron becomes storage iron, or hemosiderin. Over time, hemosiderosis involves more and more tissues of the body, particularly the liver, but also skin (bronze colour), heart (with heart fail
A patient with paroxysmal nocturnal hemoglobinuria (PNH) experiences episodes of red blood cell lysis. This results from:
- Deficiency of C1 inhibitor allowing uncontrolled classical pathway activation
- Deficiency of Factor H causing excessive alternative pathway activity
- Loss of GPI-anchored proteins DAF and CD59 that normally protect cells
- Excessive production of membrane attack complex components
- Antibody-mediated complement activation against RBC antigens
Answer: C. PNH results from acquired deficiency of the enzyme that creates GPI (glycophosphatidylinositol) anchors. This causes loss of GPI-anchored complement regulatory proteins, particularly DAF (decay accelerating factor, which prevents C3 convertase formation) and CD59 (which inhibits MAC formation). Without these protections, complement activation on the patient's own RBCs leads to MAC-mediated cell lysis. RBCs are partic
What is the shelf life of a unit of Red Blood Cells that has been 'opened' by entering the system for washing or aliquoting in an open system, if stored at 1-6°C?
- 4 hours
- 24 hours
- 7 days
- 42 days
Answer: B. Once the sterile seal of a blood unit is broken (open system), the risk of bacterial contamination requires discarding the unit within 24 hours when stored at 1–6°C. ---
Which blood type is considered the universal donor for red blood cells?
- Type A
- Type B
- Type AB
- Type O
Answer: D. Type O negative red blood cells lack both A and B antigens and the Rh factor, making them compatible with all other blood types. ---
Which blood type is considered the universal recipient for red blood cells?
- Type A
- Type B
- Type AB
- Type O
Answer: C. Type AB positive individuals have both A and B antigens and the Rh factor on their red blood cells, so they do not produce antibodies against A, B, or Rh antigens and can receive red blood cells from any ABO and Rh blood type. ---
Which antigen is present on the surface of red blood cells in Type B blood?
- A antigen
- B antigen
- AB antigen
- Rh antigen
Answer: B. Type B blood has the B antigen on the surface of its red blood cells. ---