1. Specimen collection and anticoagulants
   Venepuncture, capillary blood, EDTA, citrate, heparin, and common pre-analytical errors.
2. Hemoglobin and red-cell investigations
   Hb estimation, PCV/hematocrit, RBC count, red-cell indices, ESR, reticulocyte count, and interpretation of anemia patterns.
3. Peripheral blood smear
   Preparation and staining, normal morphology, and identification of microcytosis, macrocytosis, target cells, sickle cells, blasts, malarial parasite, etc.
4. White-cell investigations
   Total leukocyte count, differential leukocyte count, absolute counts, and smear findings in leukocytosis/leukemia.
5. Platelets and coagulation
   Platelet count, bleeding time, clotting time, PT/INR, aPTT, and basic interpretation of coagulation disorders.
6. Blood grouping and transfusion basics
   ABO/Rh typing, cross-matching, compatibility, and transfusion reactions.
7. Practical viva and spotters
   Instruments, stains, chambers, anticoagulant tubes, blood films, and calculation-based questions.

Hematology Practical Viva Questions with Short Answers

A. Blood collection and anticoagulants

1. What is hematology?
   Study of blood cells, blood-forming organs, and coagulation.
2. Which anticoagulant is used for routine CBC?
   EDTA, usually K2-EDTA.
3. Why is EDTA preferred for CBC?
   It preserves cellular morphology well and prevents clotting by binding calcium.
4. What is the usual blood-to-anticoagulant ratio in an EDTA tube?
   Approximately 1.5-2 mg EDTA per mL of blood.
5. Which anticoagulant is used for PT and aPTT?
   3.2% sodium citrate.
6. What is the blood-to-citrate ratio for coagulation tests?
   9 parts blood to 1 part citrate.
7. Why is heparin not used for peripheral smear or CBC?
   It may cause staining artifacts and clumping of leukocytes or platelets.
8. What happens if an EDTA sample is inadequately mixed?
   Microclots may form, leading to falsely low platelet or cell counts.
9. What is pseudothrombocytopenia?
   A falsely low automated platelet count, commonly due to EDTA-dependent platelet clumping.
10. What is the effect of prolonged tourniquet application?
    Hemoconcentration, causing falsely increased Hb, PCV, and cell counts.

B. Hemoglobin estimation

1. What is the normal hemoglobin value in an adult male?
   Approximately 13.5-17.5 g/dL.
2. What is the normal hemoglobin value in an adult female?
   Approximately 12-16 g/dL.
3. Which method is commonly used for hemoglobin estimation in teaching practicals?
   Sahli’s acid hematin method.
4. What is the principle of Sahli’s method?
   Hemoglobin is converted to brown-colored acid hematin using N/10 HCl and matched against a standard color.
5. What are the limitations of Sahli’s method?
   It is subjective, less accurate, and affected by visual color matching.
6. What is the reference method for hemoglobin estimation?
   Cyanmethemoglobin method, though modern analyzers use other photometric methods.
7. What is anemia?
   A reduction in hemoglobin concentration below the reference range for age, sex, and physiological state.
8. Can Hb be normal in polycythemia with dehydration?
   Yes. Dehydration causes hemoconcentration and may produce relative polycythemia.

C. RBC count, PCV, and red-cell indices

1. What is the normal RBC count in adults?
   Roughly 4.5-6.0 million/µL in males and 4.0-5.5 million/µL in females.
2. What is PCV or hematocrit?
   The percentage of blood volume occupied by packed red blood cells.
3. What is the normal PCV?
   Approximately 41%-53% in males and 36%-46% in females.
4. What is the principle of hematocrit estimation?
   Centrifugation separates packed RBCs from plasma, allowing their volume fraction to be measured.
5. What is buffy coat?
   The thin layer of leukocytes and platelets between packed RBCs and plasma after centrifugation.
6. Define MCV.
   Mean corpuscular volume, the average volume of an RBC.
7. Formula for MCV?
   MCV (fL) = PCV (%) × 10 / RBC count (million/µL).
8. Normal MCV range?
   About 80-100 fL.
9. What does low MCV indicate?
   Microcytosis, as in iron-deficiency anemia or thalassemia.
10. What does high MCV indicate?
    Macrocytosis, as in vitamin B12/folate deficiency, liver disease, alcohol use, or some drugs.
11. Define MCH.
    Mean corpuscular hemoglobin, the average mass of hemoglobin per RBC.
12. Formula for MCH?
    MCH (pg) = Hb (g/dL) × 10 / RBC count (million/µL).
13. Define MCHC.
    Mean corpuscular hemoglobin concentration, the average concentration of Hb in packed RBCs.
14. Formula for MCHC?
    MCHC (g/dL) = Hb (g/dL) × 100 / PCV (%).
15. Normal MCHC range?
    Approximately 32-36 g/dL.
16. When is MCHC increased?
    Hereditary spherocytosis, severe burns, or analytical artifact such as cold agglutinins.

D. ESR and reticulocyte count

1. What is ESR?
   Erythrocyte sedimentation rate: the distance RBCs fall in a vertical column of anticoagulated blood in one hour.
2. Which anticoagulant is classically used in the Westergren method?
   Sodium citrate.
3. What is the principle of ESR?
   Aggregated RBCs settle faster than individual RBCs under gravity.
4. Name conditions in which ESR is raised.
   Infections, inflammation, autoimmune disease, anemia, pregnancy, and malignancy.
5. Name conditions in which ESR may be low.
   Polycythemia, marked leukocytosis, sickle-cell disease, and abnormal RBC shapes.
6. What is a reticulocyte?
   An immature, non-nucleated RBC containing residual RNA.
7. Which stain is used for reticulocyte count?
   Supravital stains such as new methylene blue or brilliant cresyl blue.
8. Normal reticulocyte count?
   About 0.5%-2.5% of circulating RBCs.
9. When is reticulocyte count increased?
   Hemolysis, acute blood loss, or response to treatment of nutritional anemia.
10. Why can reticulocyte percentage be misleading in anemia?
    The percentage may appear high despite inadequate RBC production; corrected reticulocyte count or reticulocyte production index is more informative.

E. Peripheral smear and stains

1. Why is a peripheral blood smear prepared?
   To assess morphology of RBCs, WBCs, and platelets, and to detect abnormal cells or blood parasites.
2. What is a good peripheral smear?
   A tongue-shaped film with a smooth feathered edge and an area where RBCs are evenly distributed without major overlap.
3. What is the ideal area for examining RBC morphology?
   The monolayer just behind the feathered edge, where cells barely touch each other.
4. Which stains are used for peripheral blood smear?
   Romanowsky stains: Leishman, Wright, Giemsa, or May-Grünwald-Giemsa stain.
5. What are the components of Romanowsky stain?
   A basic dye such as methylene blue/azure and an acidic dye, eosin.
6. What is the role of methanol in Leishman stain?
   It fixes the blood film.
7. Why should a blood smear be air-dried quickly?
   Slow drying can cause artifacts and poor cell morphology.
8. What is rouleaux formation?
   RBCs arranged like stacks of coins, usually due to increased plasma proteins.
9. What is agglutination of RBCs?
   Irregular clumping of RBCs, often due to cold agglutinins.
10. What are target cells?
    RBCs with central hemoglobinized area surrounded by pallor and an outer rim of hemoglobin. Seen in thalassemia, liver disease, and post-splenectomy states.
11. What are spherocytes?
    Small, dense RBCs without central pallor. Seen in hereditary spherocytosis and immune hemolytic anemia.
12. What are schistocytes?
    Fragmented RBCs, seen in microangiopathic hemolytic anemia, DIC, TTP, and mechanical heart valves.
13. What are sickle cells?
    Crescent-shaped RBCs caused by polymerization of HbS under deoxygenated conditions.
14. What are Howell-Jolly bodies?
    Nuclear DNA remnants in RBCs, commonly seen after splenectomy or in hyposplenism.
15. What is basophilic stippling?
    Fine or coarse blue granules in RBCs due to aggregated ribosomal RNA; classically seen in lead poisoning and thalassemia.
16. What are hypersegmented neutrophils?
    Neutrophils with more than five nuclear lobes, typically seen in megaloblastic anemia.

F. TLC, DLC, and leukocyte morphology

1. What is TLC?
   Total leukocyte count, the total number of WBCs per microliter of blood.
2. Normal TLC in adults?
   Approximately 4,000-11,000/µL.
3. What is leukocytosis?
   Increase in total WBC count above the reference range.
4. What is leukopenia?
   Decrease in total WBC count below the reference range.
5. What is DLC?
   Differential leukocyte count, the percentage distribution of different leukocyte types.
6. Normal neutrophil percentage?
   Around 40%-70%.
7. Normal lymphocyte percentage?
   Around 20%-40%.
8. Normal monocyte percentage?
   Around 2%-8%.
9. Normal eosinophil percentage?
   Around 1%-6%.
10. Normal basophil percentage?
    Usually less than 1%.
11. What is neutrophilia?
    Increased absolute neutrophil count, often in bacterial infection, inflammation, stress, or corticosteroid use.
12. What is eosinophilia?
    Increased eosinophils, commonly seen in allergy, parasitic infestation, drug reactions, and some malignancies.
13. What is lymphocytosis?
    Increased absolute lymphocyte count, often in viral infections and some lymphoproliferative disorders.
14. What is a left shift?
    Increased immature neutrophil precursors, especially band forms, in peripheral blood.
15. What are toxic granules?
    Prominent dark granules in neutrophils, often associated with severe bacterial infection or inflammation.

G. Platelets and coagulation

1. Normal platelet count?
   Approximately 150,000-450,000/µL.
2. What is thrombocytopenia?
   Platelet count below 150,000/µL.
3. What is thrombocytosis?
   Platelet count above 450,000/µL.
4. What is the main function of platelets?
   Primary hemostasis: platelet adhesion, activation, aggregation, and formation of the platelet plug.
5. What is bleeding time?
   A historical test of platelet function and primary hemostasis. It is now largely replaced by more reliable tests.
6. What does prolonged bleeding time suggest?
   Thrombocytopenia, platelet dysfunction, or von Willebrand disease.
7. What does PT assess?
   Extrinsic and common coagulation pathways.
8. Which factors are assessed by PT?
   Factors VII, X, V, II, and fibrinogen.
9. What does aPTT assess?
   Intrinsic and common coagulation pathways.
10. Which factors are assessed by aPTT?
    Factors XII, XI, IX, VIII, X, V, II, and fibrinogen.
11. What is INR?
    International normalized ratio, a standardized expression of PT used mainly for monitoring warfarin therapy.
12. Which coagulation test is prolonged in hemophilia A?
    aPTT, due to factor VIII deficiency.
13. Which coagulation test is prolonged in vitamin K deficiency?
    PT rises early, and severe deficiency can prolong both PT and aPTT.
14. What is D-dimer?
    A fibrin degradation product indicating breakdown of cross-linked fibrin.
15. What is DIC?
    Disseminated intravascular coagulation: widespread activation of coagulation causing consumption of platelets and clotting factors, with bleeding and thrombosis.

H. Blood grouping and transfusion

1. What is the basis of ABO blood grouping?
   Presence or absence of A and B antigens on RBCs and naturally occurring antibodies in plasma.
2. What are the antibodies in blood group A?
   Anti-B antibodies.
3. What are the antibodies in blood group B?
   Anti-A antibodies.
4. Which blood group has neither A nor B antigen?
   Group O.
5. Which blood group has both A and B antigens?
   Group AB.
6. What is Rh positivity?
   Presence of D antigen on RBCs.
7. Why is Rh incompatibility important in pregnancy?
   Maternal anti-D antibodies can cause hemolytic disease of the fetus and newborn in a subsequent Rh-positive pregnancy.
8. What is cross-matching?
   Testing donor RBCs against recipient serum to detect incompatibility before transfusion.
9. What is the universal donor for packed RBCs in emergencies?
   O Rh-negative RBCs, when group-specific compatible blood is unavailable.
10. What is the universal recipient for packed RBCs?
    AB Rh-positive individuals, though group-specific compatible blood is preferred.