A 52-year-old man with diabetic kidney disease (eGFR 18 mL/min/1.73 m²) has Hb 8.4 g/dL with normocytic red cells, normal ferritin and a low reticulocyte count. Reduced erythropoietin output from which cells explains his anaemia?

Peritubular interstitial cells of the kidney

Proximal convoluted tubule epithelial cells

Macula densa cells of the distal tubule

Juxtaglomerular cells of the afferent arteriole

A 64-year-old bidi smoker with severe COPD has a resting SpO2 of 86% on room air, a haematocrit of 58% and a plethoric face. Serum erythropoietin is raised and the spleen is not enlarged. What has driven the rise in his red cell mass?

Renal hypoxia stabilising HIF, raising erythropoietin

JAK2 mutation making marrow cells grow without EPO

Raised 2,3-BPG directly stimulating red cell precursors

Smoke-induced loss of plasma volume only

A 30-year-old man had his spleen removed after a road accident two years ago. A routine smear now shows many red cells containing small, round, dark purple nuclear remnants, along with target cells. Which normal function of the spleen explains why these inclusions were absent before?

Removal of inclusions from passing red cells

Production of red cells in adult life

Storage of most of the body's iron

Synthesis of most circulating antibodies

Blood, haemostasis and immunity physiology

29 NEET-PG practice questions on Blood, haemostasis and immunity physiology, part of Physiology. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
A 32-year-old woman from Mumbai needs blood after a postpartum haemorrhage. Forward grouping shows no reaction with anti-A or anti-B, but her serum agglutinates A, B and O red cells strongly at room temperature and at 37°C. Which antigen is absent from her red cells?
1. ALewis antigen
2. BH antigen
3. CD antigen
4. DA1 antigen
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Answer: B · H antigen
She has the Bombay (Oh) phenotype, first described in Mumbai. She lacks the FUT1 enzyme that makes H substance, the precursor that A and B transferases modify, so her cells carry no H, A or B antigen and type as O. Her plasma contains anti-A, anti-B and a strong anti-H that reacts with group O cells, which carry the most H antigen. She can safely receive only Bombay blood, so rare-donor registries are used.
- A: Anti-Lewis antibodies are usually weak, IgM and of little clinical importance.
- C: Lack of D would not make her serum react with all O cells.
- D: Absence of A1 causes only a weak anti-A1 in some A2 people, not reaction with O cells.
Question 2 · Easy
A 52-year-old man with diabetic kidney disease (eGFR 18 mL/min/1.73 m²) has Hb 8.4 g/dL with normocytic red cells, normal ferritin and a low reticulocyte count. Reduced erythropoietin output from which cells explains his anaemia?
1. AProximal convoluted tubule epithelial cells
2. BMacula densa cells of the distal tubule
3. CJuxtaglomerular cells of the afferent arteriole
4. DPeritubular interstitial cells of the kidney
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Answer: D · Peritubular interstitial cells of the kidney
In adults most erythropoietin is made by interstitial (fibroblast-like) cells lying around the peritubular capillaries in the renal cortex and outer medulla, with a small share from the liver. These cells sense oxygen delivery through hypoxia-inducible factor, so a fall in tissue oxygen raises erythropoietin output. As kidney disease destroys this tissue, erythropoietin falls and a normocytic, hypoproliferative anaemia develops. Iron stores are checked and replaced before starting an erythropoiesis-stimulating agent.
- A: Proximal tubular cells reabsorb filtrate and make calcitriol; they are not the main EPO source.
- B: Macula densa cells sense distal sodium chloride and signal renin release.
- C: Juxtaglomerular cells secrete renin, not erythropoietin.
Question 3 · Medium
A 34-year-old man with liver disease from a road accident needs plasma urgently in casualty, before his blood group is known. Which group of fresh frozen plasma is safe to give?
1. AGroup A plasma
2. BGroup AB plasma
3. CGroup O plasma
4. DGroup B plasma
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Answer: B · Group AB plasma
Plasma compatibility depends on the antibodies in the donor plasma, the reverse of red cell compatibility. Group AB plasma has neither anti-A nor anti-B, so it cannot haemolyse the recipient's red cells, whatever his group; AB is therefore the universal plasma donor. Group O plasma contains anti-A and anti-B and is safe only for group O recipients. Plasma is switched to group-specific units as soon as the patient's group is known, because AB plasma is scarce.
- A: Group A plasma contains anti-B and is unsafe for B or AB recipients.
- C: Group O plasma carries anti-A and anti-B and could haemolyse A, B or AB red cells.
- D: Group B plasma contains anti-A and is unsafe for A or AB recipients.
Question 4 · Medium
A 64-year-old bidi smoker with severe COPD has a resting SpO2 of 86% on room air, a haematocrit of 58% and a plethoric face. Serum erythropoietin is raised and the spleen is not enlarged. What has driven the rise in his red cell mass?
1. AJAK2 mutation making marrow cells grow without EPO
2. BRaised 2,3-BPG directly stimulating red cell precursors
3. CSmoke-induced loss of plasma volume only
4. DRenal hypoxia stabilising HIF, raising erythropoietin
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Answer: D · Renal hypoxia stabilising HIF, raising erythropoietin
Chronic hypoxaemia lowers oxygen delivery to the kidney. In the erythropoietin-producing cells, hypoxia stops the oxygen-dependent breakdown of hypoxia-inducible factor (HIF), which then switches on the erythropoietin gene. Erythropoietin increases red cell production, raising haematocrit and oxygen-carrying capacity, but also blood viscosity. Smoking adds carboxyhaemoglobin, which worsens tissue hypoxia, so stopping smoking and correcting hypoxia with oxygen are the key steps.
- A: A JAK2 mutation causes polycythaemia vera, in which erythropoietin is low, not raised.
- B: 2,3-BPG shifts the oxygen curve right; it does not stimulate erythropoiesis.
- C: Relative polycythaemia from low plasma volume does not raise erythropoietin.
Question 5 · Medium
A 30-year-old man had his spleen removed after a road accident two years ago. A routine smear now shows many red cells containing small, round, dark purple nuclear remnants, along with target cells. Which normal function of the spleen explains why these inclusions were absent before?
1. AProduction of red cells in adult life
2. BStorage of most of the body's iron
3. CSynthesis of most circulating antibodies
4. DRemoval of inclusions from passing red cells
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Answer: D · Removal of inclusions from passing red cells
The round nuclear remnants are Howell-Jolly bodies. As red cells squeeze through the splenic cords and the narrow slits into the sinuses, macrophages remove such inclusions and leave the cell to circulate (pitting), and they destroy old or rigid cells (culling). After splenectomy, inclusions and target cells persist in the blood. The patient is at lifelong risk of overwhelming infection by capsulated bacteria and needs pneumococcal, Hib and meningococcal vaccines and advice to seek care early for fever.
- A: In adults the spleen does not make red cells; it does so only in fetal life or in disease.
- B: Iron is stored mainly in the liver and marrow macrophages, not chiefly in the spleen.
- C: The spleen makes antibodies against blood-borne antigens, but this does not remove red cell inclusions.
Question 6 · Hard
Two patients in a medical ICU have prolonged PT and aPTT and a platelet count of 80,000/µL. Patient X has decompensated alcoholic cirrhosis with ascites; patient Y has septic shock from pyelonephritis with oozing from cannula sites. Fibrinogen is low-normal in X and low in Y. Which further result best separates the two?
1. AD-dimer: high in X, normal in Y
2. BFactor VIII: normal or high in X, low in Y
3. CVitamin K-dependent factors: normal in X, low in Y
4. DFactor VII: low in X, normal in Y
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Question 7 · Medium
A 12-year-old boy from a tribal area of Odisha with sickle cell anaemia has had fewer painful crises since he was started on hydroxyurea. His HbF has risen from 6% to 18%. Why does the higher HbF reduce sickling?
1. AHbF makes the red cells more rigid
2. BHbF lowers the oxygen affinity of the cells
3. CHbF binds 2,3-BPG more strongly than HbS
4. DHbF does not join the deoxy-HbS polymer
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Question 8 · Medium
A 40-year-old man has bled excessively after a tooth extraction and after a minor operation. He takes no drugs, eats a normal diet and has normal liver function. Platelet count 2.5 lakh/µL, PT 26 s (control 12 s), aPTT 32 s (control 31 s). A 1:1 mix with normal plasma corrects the PT. Deficiency of which factor is most likely?
1. AFactor XII
2. BFactor XI
3. CFactor VIII
4. DFactor VII
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Question 9 · Medium
A 7-month-old girl from a Sindhi family is brought with pallor and poor feeding; she was well until about 4 months of age. Hb is 5.8 g/dL with microcytic, target and many nucleated red cells, and HPLC shows mostly HbF with very little HbA. Why did her illness appear only after the first few months?
1. AAlpha-chain synthesis begins only after birth
2. BGamma chains fall after birth and beta chains are needed
3. CMaternal haemoglobin protected her until then
4. DFetal red cells need beta chains to form HbF
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Question 10 · Hard
A 24-year-old group O, Rh(D)-positive primigravida delivers a group A, Rh(D)-positive baby, who becomes jaundiced on day 1; the baby's smear shows many spherocytes. Consider four statements: 1. This form of haemolytic disease can affect a first pregnancy. 2. The direct Coombs test on the baby is usually strongly positive. 3. Part of the mother's anti-A is IgG, which crosses the placenta. 4. Giving anti-D to the mother in her next pregnancy would prevent recurrence. Which statements are correct?
1. A1 and 3 only
2. B3 and 4 only
3. C1, 2 and 4 only
4. D2 and 3 only
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Question 11 · Easy
A 26-year-old Rh(D)-negative woman delivers an Rh(D)-positive baby in a district hospital. Her indirect Coombs test was negative throughout pregnancy. Within what time after delivery should anti-D immunoglobulin ideally be given?
1. AWithin 6 weeks
2. BWithin 72 hours
3. CWithin 24 hours
4. DWithin 7 days
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Question 12 · Easy
A 30-year-old woman with coeliac disease confirmed on duodenal biopsy has iron deficiency anaemia despite eating a mixed diet with green leafy vegetables. Where in the gut is dietary iron mainly absorbed?
1. AAscending colon
2. BTerminal ileum
3. CBody and antrum of the stomach
4. DDuodenum and upper jejunum
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Question 13 · Medium
A 6-day-old boy who received vitamin K at birth bleeds steadily from the umbilical stump after the cord falls off. Platelet count, PT and aPTT are all normal, but a clot formed from his plasma dissolves in 5 molar urea. Deficiency of which factor is most likely?
1. AFactor VIII
2. BFactor XIII
3. CFactor XII
4. DFactor VII
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Question 14 · Hard
A family court in Kerala asks a district hospital to help in a paternity dispute. The mother is group O, the child is group A, and the alleged father is group O. Paternity testing by DNA has not yet been done. What conclusion do the ABO groups support?
1. AThe man is proved to be the biological father
2. BThe man is excluded as the biological father
3. CThe woman is excluded as the biological mother
4. DNo conclusion is possible from ABO grouping
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Question 15 · Medium
Pre-operative screen of a boy scheduled for circumcision: PT 13 s (control 13), aPTT 68 s (control 32), platelets 2.6 lakh/µL. When his plasma is mixed 1:1 with normal plasma, the aPTT corrects to 34 s. His maternal uncle bled heavily after a tooth extraction. What do these results indicate?
1. ADeficiency of factor VII in the extrinsic pathway
2. BDeficiency of a common pathway factor such as X
3. CA circulating inhibitor such as lupus anticoagulant
4. DDeficiency of an intrinsic pathway factor such as VIII
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Question 16 · Hard
In the labour room of a district hospital at 2 a.m., a multigravida at 34 weeks with pre-eclampsia is delivered of a dead fetus after a concealed abruptio placentae with a large retroplacental clot. Despite oxytocin and a well-contracted uterus she keeps bleeding from the genital tract, the IV cannula sites and her gums, and the blood in a plain tube does not clot after 10 minutes. Results: platelets 60,000/µL, PT 24 s (control 13), aPTT 58 s (control 32), fibrinogen 80 mg/dL (normal 200-400), D-dimer markedly raised. The uterus has been emptied and red cells are being given. Which component best corrects the deficit that most threatens clot formation here?
1. AVitamin K injection
2. BTranexamic acid alone
3. CPlatelet concentrate
4. DCryoprecipitate
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Question 17 · Hard
Haemolysis is suspected in a woman with haematocrit 25%. Her reticulocyte count is 9%. Take a normal haematocrit of 45%, and a maturation time of 2 days for reticulocytes released at a haematocrit of 25%. What is her reticulocyte production index, and what does it suggest?
1. AAbout 5.0; the marrow is responding well
2. BAbout 2.5; the marrow is responding well
3. CAbout 9.0; the marrow is responding very well
4. DAbout 1.0; the marrow response is inadequate
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Question 18 · Medium
On day 3 of primaquine for vivax malaria, a man from a tribal area of Odisha passes dark urine and becomes pale; Hb falls from 13 to 8 g/dL. The smear shows bite cells, and supravital staining shows Heinz bodies. Why are his red cells unable to withstand the drug?
1. AComplement is activated because GPI-anchored proteins are missing
2. BAn abnormal globin chain makes haemoglobin precipitate on deoxygenation
3. CLow NADPH leaves too little reduced glutathione to neutralise oxidants
4. DLack of ATP from glycolysis stops the membrane sodium pump
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Question 19 · Medium
Platelet aggregation studies in a girl with lifelong gum bleeding and heavy periods: platelet count and size normal; no aggregation with ADP, collagen or adrenaline; normal agglutination with ristocetin. vWF levels are normal. Which platelet component is defective?
1. ADense granule ADP
2. Bvon Willebrand factor
3. CGlycoprotein IIb/IIIa
4. DGlycoprotein Ib-IX-V
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Question 20 · Medium
Three years after resection of 100 cm of terminal ileum for Crohn disease, a man has fatigue, a sore red tongue, numb feet and unsteadiness in the dark. Hb is 8.2 g/dL with MCV 112 fL, and his diet includes milk and eggs daily. Why has he become deficient?
1. AFolate is absorbed only in the terminal ileum
2. BPancreatic enzymes can no longer release B12 from R-binder
3. CThe B12-intrinsic factor complex is absorbed only in the terminal ileum
4. DParietal cells no longer secrete intrinsic factor
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Question 21 · Medium
Pulse oximetry reads 85% and does not improve with 60% oxygen in a leprosy patient on dapsone who complains of headache and breathlessness. Arterial PaO2 is 210 mmHg. His blood looks chocolate-brown and stays brown when shaken in air. Which treatment reverses the underlying change in his haemoglobin?
1. AIV methylene blue, reducing ferric iron through NADPH methaemoglobin reductase
2. BHyperbaric oxygen to displace carbon monoxide from haem
3. CHydroxocobalamin to bind cyanide in the blood
4. DExchange transfusion to remove sulphaemoglobin
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Question 22 · Easy
Born at home in a village and never taken to a health facility, a breastfed baby who received no injections at birth bleeds from the umbilical stump and has melaena on day 4. Platelet count is normal and PT is markedly prolonged. Which clotting factors are deficient?
1. AFactors XI and XII
2. BFactor XIII and fibrinogen
3. CFactors II, VII, IX and X
4. DFactors V and VIII
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Question 23 · Medium
A peripheral smear shows many small, dense red cells without central pallor in a schoolboy with recurrent jaundice and a palpable spleen; his mother had her spleen removed. MCHC is 37 g/dL (normal 32-36) and the direct Coombs test is negative. Which mechanism mainly shortens the life of his red cells?
1. AOxidant damage forms Heinz bodies because NADPH is lacking
2. BHaemoglobin polymerises on deoxygenation and the cells sickle
3. CAntibody-coated red cells are removed by splenic macrophages
4. DMembrane loss from a spectrin or ankyrin defect, then splenic trapping
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Question 24 · Medium
On the postnatal ward, neonatal jaundice appears at 20 hours in the first baby of a mother whose blood group is O RhD-positive; the baby is group A RhD-positive. The direct Coombs test is weakly positive and the smear shows spherocytes. Why can this happen in a first pregnancy?
1. AThe mother was sensitised to the D antigen in a previous pregnancy
2. BAnti-A in group O mothers is IgM, which crosses the placenta readily
3. CGroup O mothers have naturally occurring IgG anti-A that crosses the placenta
4. DFetal red cells enter the mother only during this first delivery
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Question 25 · Medium
Recurrent liver abscesses, perianal abscesses and staphylococcal pneumonia since infancy have brought a boy to the paediatric ward; his maternal uncle died of a fungal pneumonia, and tissue biopsies show granulomas. His neutrophil count is normal and the nitroblue tetrazolium test fails to turn blue. Which step in neutrophil killing is defective?
1. AFusion of phagosomes with lysosomes
2. BExpression of integrins needed for adhesion
3. CRelease of myeloperoxidase from granules
4. DProduction of superoxide by NADPH oxidase
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Blood, haemostasis and immunity physiology

A 32-year-old woman from Mumbai needs blood after a postpartum haemorrhage. Forward grouping shows no reaction with anti-A or anti-B, but her serum agglutinates A, B and O red cells strongly at room temperature and at 37°C. Which antigen is absent from her red cells?

A 52-year-old man with diabetic kidney disease (eGFR 18 mL/min/1.73 m²) has Hb 8.4 g/dL with normocytic red cells, normal ferritin and a low reticulocyte count. Reduced erythropoietin output from which cells explains his anaemia?

A 34-year-old man with liver disease from a road accident needs plasma urgently in casualty, before his blood group is known. Which group of fresh frozen plasma is safe to give?

A 64-year-old bidi smoker with severe COPD has a resting SpO2 of 86% on room air, a haematocrit of 58% and a plethoric face. Serum erythropoietin is raised and the spleen is not enlarged. What has driven the rise in his red cell mass?

A 30-year-old man had his spleen removed after a road accident two years ago. A routine smear now shows many red cells containing small, round, dark purple nuclear remnants, along with target cells. Which normal function of the spleen explains why these inclusions were absent before?

A 12-year-old boy from a tribal area of Odisha with sickle cell anaemia has had fewer painful crises since he was started on hydroxyurea. His HbF has risen from 6% to 18%. Why does the higher HbF reduce sickling?

A 7-month-old girl from a Sindhi family is brought with pallor and poor feeding; she was well until about 4 months of age. Hb is 5.8 g/dL with microcytic, target and many nucleated red cells, and HPLC shows mostly HbF with very little HbA. Why did her illness appear only after the first few months?

A 26-year-old Rh(D)-negative woman delivers an Rh(D)-positive baby in a district hospital. Her indirect Coombs test was negative throughout pregnancy. Within what time after delivery should anti-D immunoglobulin ideally be given?

A 30-year-old woman with coeliac disease confirmed on duodenal biopsy has iron deficiency anaemia despite eating a mixed diet with green leafy vegetables. Where in the gut is dietary iron mainly absorbed?

A 6-day-old boy who received vitamin K at birth bleeds steadily from the umbilical stump after the cord falls off. Platelet count, PT and aPTT are all normal, but a clot formed from his plasma dissolves in 5 molar urea. Deficiency of which factor is most likely?

A family court in Kerala asks a district hospital to help in a paternity dispute. The mother is group O, the child is group A, and the alleged father is group O. Paternity testing by DNA has not yet been done. What conclusion do the ABO groups support?

Pre-operative screen of a boy scheduled for circumcision: PT 13 s (control 13), aPTT 68 s (control 32), platelets 2.6 lakh/µL. When his plasma is mixed 1:1 with normal plasma, the aPTT corrects to 34 s. His maternal uncle bled heavily after a tooth extraction. What do these results indicate?

Haemolysis is suspected in a woman with haematocrit 25%. Her reticulocyte count is 9%. Take a normal haematocrit of 45%, and a maturation time of 2 days for reticulocytes released at a haematocrit of 25%. What is her reticulocyte production index, and what does it suggest?

On day 3 of primaquine for vivax malaria, a man from a tribal area of Odisha passes dark urine and becomes pale; Hb falls from 13 to 8 g/dL. The smear shows bite cells, and supravital staining shows Heinz bodies. Why are his red cells unable to withstand the drug?

Platelet aggregation studies in a girl with lifelong gum bleeding and heavy periods: platelet count and size normal; no aggregation with ADP, collagen or adrenaline; normal agglutination with ristocetin. vWF levels are normal. Which platelet component is defective?

Three years after resection of 100 cm of terminal ileum for Crohn disease, a man has fatigue, a sore red tongue, numb feet and unsteadiness in the dark. Hb is 8.2 g/dL with MCV 112 fL, and his diet includes milk and eggs daily. Why has he become deficient?

Born at home in a village and never taken to a health facility, a breastfed baby who received no injections at birth bleeds from the umbilical stump and has melaena on day 4. Platelet count is normal and PT is markedly prolonged. Which clotting factors are deficient?

On the postnatal ward, neonatal jaundice appears at 20 hours in the first baby of a mother whose blood group is O RhD-positive; the baby is group A RhD-positive. The direct Coombs test is weakly positive and the smear shows spherocytes. Why can this happen in a first pregnancy?