A 54-year-old woman with essential thrombocythemia has easy bruising and nosebleeds. Her platelet count is 1,650 × 10^9/L. Which laboratory finding most likely explains the bleeding?

Low VWF activity with loss of large multimers

Low fibrinogen with a high D-dimer

A lupus anticoagulant prolonging the APTT

Prolonged PT from factor VII deficiency

Which test is preferred for routine monitoring of response to tyrosine kinase inhibitor therapy in chronic-phase CML?

Quantitative RT-PCR for BCR::ABL1 in blood

JAK2 V617F allele burden in blood

Neutrophil alkaline phosphatase score

Bone marrow karyotype every month

Chronic myeloid leukemia and myeloproliferative neoplasms

14 DOH Abu Dhabi (HAAD) lab licensing practice questions on Chronic myeloid leukemia and myeloproliferative neoplasms, part of Hematology. The first 14 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 · Hard
A 71-year-old man has had a high WBC on three CBCs over 4 months, and his spleen is now palpable 6 cm below the costal margin. He is afebrile, CRP is normal, no infection or cancer has been found, and he takes no corticosteroids or G-CSF. Results: WBC 52.0 × 10^9/L with segmented neutrophils and bands 89%, promyelocytes, myelocytes and metamyelocytes together 4%, no blasts, monocytes 0.5 × 10^9/L and no basophilia; Hb 118 g/L (11.8 g/dL), platelets 210 × 10^9/L. The neutrophils show no dysplastic features. BCR::ABL1 is not detected, and CSF3R T618I is detected. The most likely diagnosis is:
1. ALeukemoid reaction
2. BChronic myeloid leukemia
3. CChronic neutrophilic leukemia
4. DMDS/MPN with neutrophilia
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Answer: C · Chronic neutrophilic leukemia
A sustained neutrophilia of 25 × 10^9/L or more, with 80% or more segmented neutrophils and bands, fewer than 10% immature granulocytes, no blasts, monocytes below 1 × 10^9/L and no dysplasia, together with splenomegaly and an activating CSF3R mutation, fits the WHO criteria for chronic neutrophilic leukemia. CML is excluded because BCR::ABL1 is not detected, and CML usually shows a myelocyte peak with basophilia rather than mature neutrophils. A leukemoid reaction needs a cause, such as infection, cancer or drugs, and does not carry a clonal CSF3R mutation. MDS/MPN with neutrophilia (formerly atypical CML) has dysgranulopoiesis and at least 10% immature granulocytes. Before the diagnosis is made, a plasma cell neoplasm, which can drive a reactive neutrophilia, should also be excluded.
- A: No reactive cause is found, and the clonal CSF3R mutation shows a neoplasm.
- B: BCR::ABL1 is not detected, and CML shows a myelocyte peak and basophilia.
- D: That disorder has dysgranulopoiesis and at least 10% immature granulocytes.
Question 2 · Hard
A 62-year-old man has Hb 172 g/L (17.2 g/dL), hematocrit 0.52 L/L, platelets 780 × 10^9/L and WBC 12.5 × 10^9/L. JAK2 V617F is detected and serum erythropoietin is low. The WHO hemoglobin criterion for polycythemia vera in men is more than 165 g/L. Which diagnosis fits best?
1. APolycythemia vera
2. BSecondary erythrocytosis
3. CPrimary myelofibrosis
4. DEssential thrombocythemia
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Answer: A · Polycythemia vera
The hemoglobin, the JAK2 mutation and the low erythropoietin meet WHO criteria for PV, and a marrow biopsy showing panmyelosis completes the diagnosis. Raised platelet and white cell counts are common in PV because the JAK2-mutant clone drives all three lineages. ET can only be diagnosed when PV criteria are not met, so a high platelet count must not distract from the raised hemoglobin. Getting this right matters because PV is managed with venesection to keep the hematocrit below 0.45 L/L.
- B: Secondary erythrocytosis has a normal or high erythropoietin and no JAK2 mutation.
- C: PMF would show a leukoerythroblastic film, anemia and marrow fibrosis.
- D: ET requires that the criteria for PV are not met, and here they are.
Question 3 · Hard
A 54-year-old woman with essential thrombocythemia has easy bruising and nosebleeds. Her platelet count is 1,650 × 10^9/L. Which laboratory finding most likely explains the bleeding?
1. ALow fibrinogen with a high D-dimer
2. BA lupus anticoagulant prolonging the APTT
3. CProlonged PT from factor VII deficiency
4. DLow VWF activity with loss of large multimers
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Answer: D · Low VWF activity with loss of large multimers
Very high platelet counts, usually above about 1,000 to 1,500 × 10^9/L, bind and clear the largest von Willebrand factor multimers, causing an acquired von Willebrand syndrome. VWF activity falls relative to VWF antigen and the high-molecular-weight multimers are lost, so platelet adhesion fails. The defect corrects when the platelet count is lowered. Testing VWF activity is advised before aspirin or surgery in ET with extreme thrombocytosis.
- A: Low fibrinogen with a high D-dimer suggests DIC, which is not a feature of stable ET.
- B: A lupus anticoagulant is linked with thrombosis, not bleeding.
- C: ET does not cause factor VII deficiency.
Question 4 · Medium
Which test is preferred for routine monitoring of response to tyrosine kinase inhibitor therapy in chronic-phase CML?
1. AJAK2 V617F allele burden in blood
2. BNeutrophil alkaline phosphatase score
3. CBone marrow karyotype every month
4. DQuantitative RT-PCR for BCR::ABL1 in blood
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Answer: D · Quantitative RT-PCR for BCR::ABL1 in blood
Real-time quantitative RT-PCR on peripheral blood measures BCR::ABL1 transcripts against a control gene and can detect about one leukemic cell in 100,000. It is done about every 3 months and reported on the International Scale (IS), where 0.1% or less is a major molecular response. Marrow karyotyping is used at diagnosis and when treatment fails, not routinely. Results are most reliable when the same laboratory and assay are used over time.
- A: JAK2 V617F is not the driver of CML.
- B: The NAP score does not measure residual disease.
- C: Monthly marrow karyotypes are invasive and far less sensitive than PCR.
Question 5 · Hard
A CML monitoring sample contains 150 BCR::ABL1 copies and 50,000 ABL1 control-gene copies. The laboratory's conversion factor to the International Scale (IS) is 0.7. What is the BCR::ABL1 result on the IS?
1. A0.21%
2. B0.0021%
3. C0.30%
4. D0.43%
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Answer: A · 0.21%
First find the raw ratio: 150 ÷ 50,000 × 100 = 0.30%. Then multiply by the laboratory's conversion factor: 0.30% × 0.7 = 0.21% IS. The conversion factor aligns each laboratory's assay with the international standard so that results can be compared between centers. A value of 0.21% is above the 0.1% IS threshold for a major molecular response.
- B: 0.0021% leaves out the multiplication by 100.
- C: 0.30% is the raw ratio before the conversion factor is applied.
- D: 0.43% comes from dividing by the conversion factor instead of multiplying.
Question 6 · Easy
Which stain is used on a bone marrow trephine biopsy to grade the fibrosis of primary myelofibrosis?
1. AReticulin (silver) stain
2. BSudan black B stain
3. CPerls' Prussian blue stain
4. DPeriodic acid-Schiff stain
Answer and explanation in LearnFree account
Question 7 · Hard
A 70-year-old woman has had JAK2-positive polycythemia vera for 12 years, controlled by venesection. In the past year she has needed none; Hb is now 98 g/L (9.8 g/dL), her spleen is enlarging, and the film shows teardrop cells, nucleated red cells, myelocytes and 3% blasts. The most likely explanation is:
1. APost-polycythemia vera myelofibrosis
2. BIron deficiency from repeated venesection
3. CTransformation to acute myeloid leukemia
4. DDevelopment of chronic myeloid leukemia
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Question 8 · Medium
In a sustained thrombocytosis, which additional finding most favors essential thrombocythemia over a reactive cause?
1. AA CALR exon 9 mutation
2. BHowell-Jolly bodies on the film
3. CIron deficiency on iron studies
4. DA markedly raised CRP
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Question 9 · Hard
A 45-year-old man has WBC 140 × 10^9/L with a myelocyte peak, basophilia and splenomegaly. The marrow karyotype is 46,XY in all 20 metaphases, but FISH shows a BCR::ABL1 fusion and RT-PCR detects an e14a2 (p210) transcript. The best interpretation is:
1. AAtypical CML (MDS/MPN with neutrophilia)
2. BCML with a cryptic BCR::ABL1 rearrangement
3. CChronic neutrophilic leukemia
4. DA false-positive FISH result
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Question 10 · Medium
A hypercellular marrow with marked granulocytic hyperplasia contains many small megakaryocytes with hypolobated nuclei ('dwarf' forms). This picture most suggests:
1. APrimary myelofibrosis
2. BEssential thrombocythemia
3. CPolycythemia vera
4. DChronic myeloid leukemia
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Question 11 · Easy
Under the WHO classification, essential thrombocythemia requires a sustained platelet count of at least:
1. A600 × 10^9/L
2. B400 × 10^9/L
3. C450 × 10^9/L
4. D1,000 × 10^9/L
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Question 12 · Medium
A patient has a neutrophilia with a left shift. The neutrophil alkaline phosphatase (NAP) score is 8 (reference 40 to 100). Which condition does this result support?
1. AChronic neutrophilic leukemia
2. BChronic myeloid leukemia
3. CPolycythemia vera
4. DNeutrophilic leukemoid reaction
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Question 13 · Easy
In typical chronic myeloid leukemia, the BCR::ABL1 fusion gene encodes a tyrosine kinase of which size?
1. Ap145
2. Bp230
3. Cp210
4. Dp190
Answer and explanation in LearnFree account
Question 14 · Medium
The JAK2 V617F mutation is found in most cases of which disorder?
1. APolycythemia vera
2. BImmune thrombocytopenia
3. CAplastic anemia
4. DChronic myeloid leukemia
Answer and explanation in LearnFree account

Chronic myeloid leukemia and myeloproliferative neoplasms

A 62-year-old man has Hb 172 g/L (17.2 g/dL), hematocrit 0.52 L/L, platelets 780 × 10^9/L and WBC 12.5 × 10^9/L. JAK2 V617F is detected and serum erythropoietin is low. The WHO hemoglobin criterion for polycythemia vera in men is more than 165 g/L. Which diagnosis fits best?

A 54-year-old woman with essential thrombocythemia has easy bruising and nosebleeds. Her platelet count is 1,650 × 10^9/L. Which laboratory finding most likely explains the bleeding?

Which test is preferred for routine monitoring of response to tyrosine kinase inhibitor therapy in chronic-phase CML?

A CML monitoring sample contains 150 BCR::ABL1 copies and 50,000 ABL1 control-gene copies. The laboratory's conversion factor to the International Scale (IS) is 0.7. What is the BCR::ABL1 result on the IS?

Which stain is used on a bone marrow trephine biopsy to grade the fibrosis of primary myelofibrosis?

In a sustained thrombocytosis, which additional finding most favors essential thrombocythemia over a reactive cause?

A 45-year-old man has WBC 140 × 10^9/L with a myelocyte peak, basophilia and splenomegaly. The marrow karyotype is 46,XY in all 20 metaphases, but FISH shows a BCR::ABL1 fusion and RT-PCR detects an e14a2 (p210) transcript. The best interpretation is:

A hypercellular marrow with marked granulocytic hyperplasia contains many small megakaryocytes with hypolobated nuclei ('dwarf' forms). This picture most suggests:

Under the WHO classification, essential thrombocythemia requires a sustained platelet count of at least:

A patient has a neutrophilia with a left shift. The neutrophil alkaline phosphatase (NAP) score is 8 (reference 40 to 100). Which condition does this result support?

In typical chronic myeloid leukemia, the BCR::ABL1 fusion gene encodes a tyrosine kinase of which size?

The JAK2 V617F mutation is found in most cases of which disorder?