Hematology Laboratory Prometric exam questions with answers

1. Question 1Automation, Flow Cytometry and Quality Controlmedium

   A healthy patient has a platelet count of 35 x 10^9/L with no bleeding, and the analyser flags platelet clumps. The film shows large platelet aggregates. What should the laboratory do?

   1. AReport the count and phone it as critical
   2. BRepeat on the same EDTA tube after mixing
   3. CRecollect in sodium citrate and examine a fresh film
   4. DRequest a bone marrow aspirate
   Show answer and explanation▾

   Answer: C. Recollect in sodium citrate and examine a fresh film

   EDTA-dependent platelet clumping causes pseudothrombocytopenia, and recollection into citrate (correcting for dilution) gives a more accurate count. Reporting the falsely low count could lead to unnecessary investigations or treatment.

2. Question 2Haemoglobinopathies and Thalassaemiashard

   A 3-month-old infant's sickle solubility test is negative, but HPLC shows a peak in the HbS window. Why might the solubility test be falsely negative?

   1. AHigh HbF levels in early infancy
   2. BToo much reducing agent in the reagent
   3. CA high haematocrit
   4. DExcess lipids in the sample
   Show answer and explanation▾

   Answer: A. High HbF levels in early infancy

   Infants under about 6 months have high HbF and low HbS concentrations, so the solubility test can be falsely negative; HPLC or electrophoresis is used for neonatal screening. Severe anaemia can also cause false negatives because of low total haemoglobin.

3. Question 3Haematopoiesis and Blood Cell Morphologymedium

   Small, irregular basophilic granules are seen near the periphery of some red cells. Which stain confirms that they contain iron?

   1. APerls Prussian blue
   2. BNew methylene blue
   3. CPeriodic acid-Schiff
   4. DSudan black B
   Show answer and explanation▾

   Answer: A. Perls Prussian blue

   Pappenheimer bodies contain iron, which stains blue with Perls Prussian blue; the cells are then called siderocytes. New methylene blue is a supravital stain for reticulocytes and Heinz bodies, not for iron.

4. Question 4Haemoglobinopathies and Thalassaemiasmedium

   A microcytic sample has MCV 62 fL and RBC 5.8 x 10^12/L. What is the Mentzer index and what does it suggest?

   1. A10.7, favouring thalassaemia trait
   2. B10.7, favouring iron deficiency
   3. C16.4, favouring thalassaemia trait
   4. D16.4, favouring iron deficiency
   Show answer and explanation▾

   Answer: A. 10.7, favouring thalassaemia trait

   Mentzer index = MCV / RBC = 62 / 5.8 = 10.7, and a value below 13 favours thalassaemia trait because the red cell count is relatively preserved. Iron deficiency typically gives a value above 13, but confirmation always requires iron studies and HbA2.

5. Question 5Specimen Handling, Laboratory Safety and Ethicseasy

   What is the minimum requirement for patient identification before blood collection?

   1. AThe room or bed number
   2. BAt least two independent identifiers
   3. CThe patient's first name only
   4. DThe diagnosis on the request form
   Show answer and explanation▾

   Answer: B. At least two independent identifiers

   At least two independent identifiers such as full name and date of birth or medical record number must be confirmed and match the request and labels. Room or bed numbers are not acceptable identifiers.

6. Question 6Haemostasis and Coagulationmedium

   A citrate tube is filled to only 60% of its nominal volume. What effect is expected on the clotting times?

   1. AFalsely shortened PT and APTT
   2. BNo effect on clotting times
   3. CFalsely prolonged PT and APTT
   4. DProlonged PT with shortened APTT
   Show answer and explanation▾

   Answer: C. Falsely prolonged PT and APTT

   Underfilling leaves excess citrate, which binds the calcium added during testing and falsely prolongs both PT and APTT. Such samples should be rejected and recollected.

7. Question 7Special Haematology Testshard

   A patient has haemolytic anaemia with haemoglobinuria, a negative DAT and a venous thrombosis. Which test is preferred to diagnose paroxysmal nocturnal haemoglobinuria?

   1. AHam acidified serum haemolysis test
   2. BSucrose lysis test on fresh blood
   3. CFlow cytometry with FLAER for GPI proteins
   4. DOsmotic fragility on incubated blood
   Show answer and explanation▾

   Answer: C. Flow cytometry with FLAER for GPI proteins

   High-sensitivity flow cytometry detecting loss of GPI-anchored proteins (for example FLAER and CD24 on granulocytes, FLAER and CD14 on monocytes) is the diagnostic standard for PNH. The Ham and sucrose lysis tests are obsolete and less sensitive.

8. Question 8White Cell Disorders and Haematological Malignancyeasy

   A white cell count is 4.0 x 10^9/L with 25% neutrophils. What is the absolute neutrophil count?

   1. A0.25 x 10^9/L
   2. B2.5 x 10^9/L
   3. C4.0 x 10^9/L
   4. D1.0 x 10^9/L
   Show answer and explanation▾

   Answer: D. 1.0 x 10^9/L

   Absolute neutrophil count = total WBC x neutrophil fraction = 4.0 x 0.25 = 1.0 x 10^9/L, which is moderate neutropenia. The percentage alone can be misleading when the total white count is abnormal.

9. Question 9Haemostasis and Coagulationmedium

   A pregnant woman with renal impairment is on treatment-dose enoxaparin. Which test is used to measure its anticoagulant effect when monitoring is needed?

   1. AAPTT
   2. BAnti-Xa activity
   3. CThrombin time
   4. DProthrombin time
   Show answer and explanation▾

   Answer: B. Anti-Xa activity

   Low molecular weight heparin acts mainly against factor Xa, and its effect is measured with a chromogenic anti-Xa assay calibrated for LMWH, usually 3-4 hours after a dose. The APTT is relatively insensitive to LMWH.

10. Question 10Red Cell Disorders and Anaemiamedium

    A film shows oval macrocytes and neutrophils with six nuclear lobes. Which deficiency is most likely?

    1. AB12 or folate deficiency
    2. BIron deficiency
    3. CCopper deficiency
    4. DVitamin K deficiency
    Show answer and explanation▾

    Answer: A. B12 or folate deficiency

    Oval macrocytes and hypersegmented neutrophils (five or more lobes in a significant proportion, or any with six) are characteristic of megaloblastic anaemia from B12 or folate deficiency. Iron deficiency causes microcytosis.

11. Question 11Specimen Handling, Laboratory Safety and Ethicsmedium

    During a multi-tube venepuncture, which tube should be collected before the EDTA tube to avoid contaminating it with EDTA?

    1. ASodium fluoride tube
    2. BSodium citrate tube
    3. CNo tube; EDTA is always first
    4. DAny tube in any order
    Show answer and explanation▾

    Answer: B. Sodium citrate tube

    The recommended order is blood cultures, citrate, serum, heparin, EDTA and then fluoride, so the citrate coagulation tube is drawn before EDTA. EDTA carryover chelates calcium and can falsely prolong clotting tests.

12. Question 12Specimen Handling, Laboratory Safety and Ethicsmedium

    A technologist suspects a tube has broken inside a closed centrifuge during a run. What should be done first?

    1. AOpen the lid at once to inspect
    2. BRestart the run to finish the samples
    3. CLeave the lid closed for about 30 minutes to let aerosols settle
    4. DSpray disinfectant through the lid vent immediately
    Show answer and explanation▾

    Answer: C. Leave the lid closed for about 30 minutes to let aerosols settle

    If breakage is suspected while the centrifuge is running, the motor is switched off and the lid left closed for about 30 minutes to allow aerosols to settle before cleanup with appropriate PPE. Opening immediately risks inhaling infectious aerosols.

13. Question 13White Cell Disorders and Haematological Malignancymedium

    A 35-year-old has pancytopenia, abnormal promyelocytes with bundles of Auer rods, low fibrinogen and a raised D-dimer. Which genetic abnormality is expected?

    1. At(9;22) BCR-ABL1
    2. Bt(8;21) RUNX1-RUNX1T1
    3. Cinv(16) CBFB-MYH11
    4. Dt(15;17) PML-RARA
    Show answer and explanation▾

    Answer: D. t(15;17) PML-RARA

    Acute promyelocytic leukaemia carries the PML-RARA fusion, usually from t(15;17), and presents with coagulopathy; it is a medical emergency. t(9;22) is the Philadelphia translocation of CML and some ALL.

14. Question 14White Cell Disorders and Haematological Malignancymedium

    Blasts in a new acute leukaemia are being characterised. Which cytochemical result supports myeloid rather than lymphoid lineage?

    1. ABlock positivity with periodic acid-Schiff
    2. BMyeloperoxidase in 3% or more of blasts
    3. CTartrate-resistant acid phosphatase
    4. DNegative staining with Sudan black B
    Show answer and explanation▾

    Answer: B. Myeloperoxidase in 3% or more of blasts

    Myeloperoxidase positivity in 3% or more of blasts indicates myeloid lineage. Coarse block PAS positivity is more typical of lymphoblasts, although immunophenotyping is now the main method for lineage assignment.

15. Question 15White Cell Disorders and Haematological Malignancymedium

    A patient with severe pneumonia has a neutrophilia of 45 x 10^9/L with toxic granulation and Dohle bodies but no basophilia. Which finding best distinguishes this from CML?

    1. AAbsence of BCR-ABL1 on molecular testing
    2. BPresence of myelocytes on the film
    3. CA raised white cell count
    4. DSplenomegaly on examination
    Show answer and explanation▾

    Answer: A. Absence of BCR-ABL1 on molecular testing

    A leukaemoid reaction is reactive and lacks BCR-ABL1, whereas CML is defined by it. Myelocytes can appear in both conditions, so their presence does not distinguish them.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.