Hematology: hemoglobin and anemia

22 Kerala PSC Lab Technician Gr II practice questions on Hematology: hemoglobin and anemia, part of Pathology. The first 22 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Easy

   What is the globin chain make-up of fetal hemoglobin (HbF)?

   1. ATwo alpha and two gamma chains
   2. BTwo alpha and two delta chains
   3. CTwo alpha and two beta chains
   4. DFour gamma chains

   Show answerHide answer

   Answer: A · Two alpha and two gamma chains

   HbF (α2γ2) is the main hemoglobin of the fetus and of the newborn, and it falls to adult levels (below about 1%) during infancy. It binds 2,3-BPG poorly, so its higher oxygen affinity helps the fetus take oxygen from maternal blood. HbF resists denaturation by alkali, which is the basis of the alkali denaturation test. Adult HbA is α2β2 and HbA2 is α2δ2.

   • B: Two alpha and two delta chains is HbA2, a minor adult hemoglobin.
   • C: Two alpha and two beta chains is HbA, the main adult hemoglobin.
   • D: Four gamma chains is Hb Bart's, seen in alpha thalassemia.

2. Question 2 · Medium

   A healthy 20-year-old student has Hb 11.2 g/dL, RBC 6.1 million/µL, MCV 62 fL and a normal serum ferritin. Which test best confirms the likely diagnosis?

   1. AReticulocyte count
   2. BHbA2 estimation by HPLC
   3. CSlide sickling test
   4. DSerum iron and TIBC

   Show answerHide answer

   Answer: B · HbA2 estimation by HPLC

   A high red cell count with a very low MCV and normal ferritin suggests beta-thalassemia trait rather than iron deficiency; the Mentzer index (MCV ÷ RBC) is 10, below 13. A raised HbA2 (above 3.5%) on HPLC or electrophoresis confirms the trait. Finding carriers matters for genetic counselling before marriage or pregnancy. Iron deficiency should still be excluded, because it can lower HbA2 and hide the trait.

   • A: A reticulocyte count shows marrow response but does not identify the cause.
   • C: The sickling test detects hemoglobin S, which does not cause this microcytic picture.
   • D: Ferritin is already normal, so iron studies add little and do not confirm thalassemia.

3. Question 3 · Easy

   Into which compound does Sahli's method convert hemoglobin?

   1. ACyanmethemoglobin
   2. BAlkaline hematin
   3. COxyhemoglobin
   4. DAcid hematin

   Show answerHide answer

   Answer: D · Acid hematin

   In Sahli's method, 20 µL of blood is added to 0.1 N hydrochloric acid, which lyses the red cells and converts hemoglobin to brown acid hematin. After about 10 minutes the solution is diluted with distilled water, drop by drop, until its colour matches the brown glass standard, and hemoglobin is read in g/dL from the graduated tube. Visual matching and incomplete conversion make it less accurate than the cyanmethemoglobin method.

   • A: Cyanmethemoglobin is formed by Drabkin's reagent.
   • B: Alkaline hematin is formed with sodium hydroxide, in a different method.
   • C: Oxyhemoglobin is measured in the oxyhemoglobin (ammonia) method, not in Sahli's.

4. Question 4 · Hard

   A 34-year-old woman, a strict vegan for 8 years, has tiredness and tingling in both feet. Hb 8.2 g/dL, MCV 114 fL, reticulocytes 0.6%; the smear shows oval macrocytes and neutrophils with six lobes. The most likely cause is:

   1. AVitamin B12 deficiency
   2. BFolic acid deficiency
   3. CIron deficiency
   4. DChronic liver disease

   Show answerHide answer

   Answer: A · Vitamin B12 deficiency

   Oval macrocytes, hypersegmented neutrophils and a low reticulocyte count show a megaloblastic anemia. Both B12 and folate deficiency cause this blood picture, but tingling feet point to the nerve damage (subacute combined degeneration) seen only in B12 deficiency. A strict vegan diet lacks B12, which comes only from animal foods, while folate is plentiful in leafy vegetables. Serum B12 confirms it; giving folate alone can worsen the nerve damage.

   • B: Folate deficiency gives the same blood picture but not neuropathy, and a vegan diet is rich in folate.
   • C: Iron deficiency causes a microcytic, not macrocytic, anemia.
   • D: Liver disease gives round macrocytes and target cells, without hypersegmented neutrophils.

5. Question 5 · Medium

   What is the role of potassium ferricyanide in Drabkin's reagent?

   1. AShortens the conversion time
   2. BConverts methemoglobin to cyanmethemoglobin
   3. CLyses the red cells
   4. DOxidises hemoglobin to methemoglobin

   Show answerHide answer

   Answer: D · Oxidises hemoglobin to methemoglobin

   Drabkin's reagent works in two steps. Potassium ferricyanide oxidises the ferrous iron of hemoglobin to the ferric form (methemoglobin), and potassium cyanide then converts methemoglobin to stable cyanmethemoglobin, read at 540 nm. Potassium dihydrogen phosphate shortens the conversion time, and a non-ionic detergent speeds lysis and reduces turbidity. All forms except sulfhemoglobin are converted, which is why this is the reference method.

   • A: Potassium dihydrogen phosphate shortens the conversion time.
   • B: Potassium cyanide, not ferricyanide, converts methemoglobin to cyanmethemoglobin.
   • C: Lysis comes from the hypotonic reagent, helped by its detergent.

6. Question 6 · Medium

   Why is the cyanmethemoglobin method preferred to Sahli's method for hemoglobin estimation?

   1. AIt is not affected by turbidity in the sample
   2. BIt needs no colorimeter or spectrophotometer
   3. CIts colour develops instantly when acid is added
   4. DIt measures nearly all forms against a stable standard

   Answer and explanation in LearnFree account

7. Question 7 · Medium

   A 32-year-old woman with heavy periods has Hb 8.9 g/dL and MCV 68 fL. Which set of iron studies is expected?

   1. ALow ferritin, high TIBC
   2. BLow ferritin, low TIBC
   3. CHigh ferritin, low TIBC
   4. DHigh ferritin, high saturation

   Answer and explanation in LearnFree account

8. Question 8 · Easy

   In sickle hemoglobin (HbS), which amino acid replaces glutamic acid at position 6 of the beta chain?

   1. AGlycine
   2. BAlanine
   3. CValine
   4. DLysine

   Answer and explanation in LearnFree account

9. Question 9 · Hard

   A 25-year-old man develops dark urine and jaundice 3 days after starting primaquine for vivax malaria. Hb has fallen from 13.5 to 8.5 g/dL and reticulocytes are 8%. The smear shows bite cells, and a supravital stain shows Heinz bodies. The most likely cause is:

   1. AWarm autoimmune hemolytic anemia
   2. BG6PD deficiency
   3. CSickle cell crisis
   4. DHereditary spherocytosis

   Answer and explanation in LearnFree account

10. Question 10 · Easy

    Which form of hemoglobin cannot carry oxygen because its iron is in the ferric (Fe³⁺) state?

    1. ADeoxyhemoglobin
    2. BCarboxyhemoglobin
    3. COxyhemoglobin
    4. DMethemoglobin

    Answer and explanation in LearnFree account

11. Question 11 · Medium

    All of the following cause a microcytic hypochromic anemia EXCEPT:

    1. AIron deficiency
    2. BSideroblastic anemia
    3. CVitamin B12 deficiency
    4. DBeta thalassemia trait

    Answer and explanation in LearnFree account

12. Question 12 · Hard

    In the cyanmethemoglobin method, blood is diluted 1 in 251. The test reads 0.36 and a 60 mg/dL cyanmethemoglobin standard reads 0.45. What is the hemoglobin?

    1. A15.1 g/dL
    2. B12.0 g/dL
    3. C4.8 g/dL
    4. D18.8 g/dL

    Answer and explanation in LearnFree account

13. Question 13 · Medium

    In a patient with suspected hemolytic anemia, which serum finding most supports intravascular hemolysis?

    1. ALow LDH
    2. BRaised direct bilirubin only
    3. CLow reticulocyte count
    4. DLow haptoglobin

    Answer and explanation in LearnFree account

14. Question 14 · Easy

    Which acid is used in Sahli's hemoglobinometer?

    1. A3% nitric acid
    2. B0.1 N hydrochloric acid
    3. C1% acetic acid
    4. D0.1 N sulphuric acid

    Answer and explanation in LearnFree account

15. Question 15 · Medium

    In Sahli's method, the blood-acid mixture is left to stand for about 10 minutes before dilution. Why?

    1. ATo allow carbon dioxide to escape
    2. BTo let the red cell stroma settle
    3. CTo allow full conversion to acid hematin
    4. DTo let the colour fade to a stable level

    Answer and explanation in LearnFree account

16. Question 16 · Hard

    A 9-year-old tribal boy from Wayanad has anemia and painful swelling of the hands. Hb 7.2 g/dL, MCV 86 fL; sickling test positive. HPLC: HbS 89%, HbF 8.2%, HbA2 2.8%, HbA 0%. The most likely diagnosis is:

    1. AHbS-beta0 thalassemia
    2. BSickle cell anemia (HbSS)
    3. CSickle cell trait (HbAS)
    4. DHbS-beta+ thalassemia

    Answer and explanation in LearnFree account

17. Question 17 · Medium

    A 55-year-old woman with long-standing rheumatoid arthritis has Hb 9.8 g/dL and MCV 79 fL. Which iron study pattern is most likely?

    1. ANormal serum iron, normal TIBC, normal ferritin
    2. BLow serum iron, high TIBC, low ferritin
    3. CLow serum iron, low TIBC, high ferritin
    4. DHigh serum iron, low TIBC, high ferritin

    Answer and explanation in LearnFree account

18. Question 18 · Easy

    By WHO criteria, a non-pregnant adult woman is anemic when her hemoglobin is below:

    1. A13 g/dL
    2. B10 g/dL
    3. C12 g/dL
    4. D11 g/dL

    Answer and explanation in LearnFree account

19. Question 19 · Easy

    At what wavelength is the colour read in the cyanmethemoglobin method?

    1. A540 nm
    2. B420 nm
    3. C620 nm
    4. D340 nm

    Answer and explanation in LearnFree account

20. Question 20 · Medium

    A rise in red cell 2,3-bisphosphoglycerate (2,3-BPG), as at high altitude, has which effect on hemoglobin?

    1. AIt has no effect on oxygen binding
    2. BIt converts hemoglobin to methemoglobin
    3. CIt lowers oxygen affinity, aiding release
    4. DIt raises oxygen affinity, aiding uptake

    Answer and explanation in LearnFree account

21. Question 21 · Medium

    In the solubility test for HbS, why does blood containing HbS make the tube turbid?

    1. AHbS cells resist lysis by saponin
    2. BHbS binds the detergent and forms a gel
    3. CHbS is oxidised to methemoglobin and precipitates
    4. DReduced HbS is insoluble in strong phosphate buffer

    Answer and explanation in LearnFree account

22. Question 22 · Easy

    In a healthy adult, HbA2 forms about what proportion of total hemoglobin?

    1. ALess than 1%
    2. B1.5-3.5%
    3. C95-98%
    4. D10-20%

    Answer and explanation in LearnFree account