MLT GlobeHematology: WBC morphology & differential – page 4
109 Hematology MCQs on WBC morphology & differential with answers and explanations.
What is the last stage of the neutrophil series that is still able to divide?
The myelocyte is the last stage capable of mitosis; from the metamyelocyte onward cells only mature. Promyelocytes also divide but are not the last dividing stage.
When classifying a neutrophil as a segmented form rather than a band, the key feature is:
A segmented neutrophil has lobes connected by a thin chromatin filament. A band has a curved nucleus of roughly even width without a filament.
Basophil granules sometimes appear as empty spaces on a Wright-stained smear because their contents are:
Basophil granules (histamine, heparin) are water-soluble and can wash out during staining, leaving clear areas. This is not a methanol or EDTA effect.
An uncorrected WBC count is 15.0 × 10^9/L. The differential shows 25 NRBCs per 100 WBCs. The corrected WBC count is:
Corrected WBC = uncorrected WBC × 100/(100 + NRBC) = 15.0 × 100/125 = 12.0 × 10^9/L. Subtracting 25% (11.3) is a common error.
Which condition can falsely raise the WBC count on an impedance cell counter?
NRBC nuclei survive lysis and are sized like lymphocytes, so they are counted as WBCs unless corrected. Bilirubin affects hemoglobin measurement rather than WBC count.
A child with partial albinism and repeated pyogenic infections has neutrophils with huge, fused grey-red cytoplasmic granules. The most likely disorder is:
Chediak-Higashi syndrome (LYST mutation) shows giant fused lysosomal granules, oculocutaneous albinism and poor killing of bacteria. Alder-Reilly granules are small and dense, without infections.
A healthy adult has mild thrombocytopenia, giant platelets and pale-blue Döhle-like inclusions in neutrophils. Which gene is involved?
May-Hegglin anomaly is an MYH9-related disorder with Döhle-like inclusions and giant platelets. LBR causes Pelger-Huët anomaly.
Dark, coarse granules in neutrophils, lymphocytes and monocytes of a child with a mucopolysaccharidosis such as Hurler syndrome are called:
Alder-Reilly granules are partly digested mucopolysaccharides in all leukocyte types. Toxic granulation is confined to neutrophils and linked to infection.
What is the main practical risk of not recognizing Pelger-Huët cells in a differential count?
Bilobed or round Pelger-Huët nuclei may be counted as bands or metamyelocytes, suggesting a left shift. The cells function normally.
Which feature best favors reactive lymphocytes over lymphoblasts on a smear?
Reactive lymphocytes form a heterogeneous population with varied size and cytoplasm. Blasts are monotonous, with fine chromatin, nucleoli and high N:C ratio.
Large granular lymphocytes with azurophilic cytoplasmic granules are most often:
LGLs are NK cells (CD16, CD56) or cytotoxic T cells (CD8, CD57); the granules contain perforin and granzymes. B cells and helper T cells lack these granules.
Plasma cells filled with multiple round pink-to-blue globules (Mott cells) contain:
Russell bodies are immunoglobulin stored in dilated rough endoplasmic reticulum; many such globules form a Mott cell. They are not phagocytic material.
Döhle bodies seen in neutrophils during infection are composed of:
Döhle bodies are pale-blue patches of rough ER/rRNA. Aggregated primary granules would appear as toxic granulation, not Döhle bodies.
An EDTA sample left 30 hours at room temperature is smeared. Neutrophils show vacuoles and nuclear swelling, but the patient is well. The best interpretation is:
Prolonged EDTA storage causes cytoplasmic vacuolation, crenation and nuclear changes. Smears should be made within a few hours of collection.
On most automated analyzers, the 'immature granulocyte' (IG) count includes:
The IG parameter counts promyelocytes, myelocytes and metamyelocytes. Bands are counted with neutrophils and blasts are flagged separately.
A healthy 2-year-old has a WBC of 10 × 10^9/L with 60% lymphocytes. The best interpretation is:
Young children normally have lymphocyte predominance, with neutrophils becoming dominant after about age 4–5. Adult ranges should not be applied.
Where on a wedge smear should the differential count be performed?
The count is done in the monolayer where RBCs barely touch. Large cells collect at edges and the feathered end, and the thick area distorts morphology.
A patient on chemotherapy has WBC 2.0 × 10^9/L with 30% segmented neutrophils and 5% bands. The absolute neutrophil count and category are:
ANC = 2.0 × (0.30 + 0.05) = 0.70 × 10^9/L. Values 0.5–1.0 are moderate; below 0.5 is severe.
A healthy adult of West African descent has a stable neutrophil count of 1.2 × 10^9/L, no infections and a normal marrow. Which red cell phenotype is commonly associated?
Duffy-null-associated neutrophil count (ACKR1 variant) causes a benign lower neutrophil count. It needs no treatment and should not be confused with pathologic neutropenia.
A patient with fever after a tick bite has leukopenia and small basophilic berry-like clusters in the cytoplasm of neutrophils. The most likely organism is:
Anaplasma forms morulae in neutrophils (Ehrlichia chaffeensis mainly in monocytes). Babesia infects red cells, not leukocytes.