MLT GlobeHematology: WBC morphology & differential – page 5
109 Hematology MCQs on WBC morphology & differential with answers and explanations.
After release from the marrow, neutrophils stay in the circulating blood for about:
Neutrophils have a blood half-life of about 7 hours before moving into tissues, where they live 1–2 days. 120 days is the red cell life span; 7–10 days is the platelet life span.
A patient's WBC rises from 6 to 11 × 10^9/L within minutes after hard exercise, with no left shift. The best explanation is:
About half of blood neutrophils adhere to vessel walls (marginal pool). Exercise, stress or epinephrine release them into the circulating pool within minutes, without immature cells.
A patient on high-dose corticosteroids is most likely to show which pattern?
Corticosteroids release neutrophils and reduce their exit into tissues, while lymphocytes and eosinophils fall. Eosinophilia can be seen when cortisol is lacking, as in adrenal insufficiency.
Which finding defines neutrophil hypersegmentation on a blood smear?
Hypersegmentation (≥5% with five lobes or any six-lobed cell) is an early sign of megaloblastic anemia from B12 or folate deficiency. Two round joined lobes describe Pelger-Huët cells.
A cell in a marrow aspirate has a round central nucleus fully visible, and many dark purple granules that do not cover the nucleus. It is larger than a basophil. It is most likely a:
Mast cells are large tissue cells with a round nucleus and dense purple granules; they are found in marrow and tissue, not normal blood. Basophil granules usually cover and obscure a lobed nucleus.
A Wright-stained smear shows red cells bluish-grey, eosinophil granules grey-blue and dark nuclei. The most likely cause is:
An alkaline stain or buffer makes everything too blue, including red cells and eosinophil granules. A pH that is too acidic gives bright red cells, pale nuclei and very red eosinophil granules.
A Wright-stained smear shows bright red cells, very pale blue nuclei and brilliant red eosinophil granules. The first thing to check is:
Overly acidic buffer (below about pH 6.4) causes too much eosin uptake and weak nuclear staining. Long staining or thick smears generally make slides too blue.
On a poorly spread wedge smear, large cells such as monocytes and neutrophils tend to collect at the:
Large cells are pushed to the edges and tail during spreading, so counting only there overestimates them. A proper battlement or systematic pattern in the monolayer area reduces this bias.
A patient with disseminated fungal infection has small oval yeasts, each with a clear halo, inside monocytes and neutrophils on a blood smear. The organism is most likely:
Histoplasma yeasts (2–4 µm) are seen within phagocytes in disseminated disease, especially in immunosuppressed patients. Anaplasma forms morulae, and Plasmodium and Babesia infect red cells.
A marrow smear from a patient with fever and massive splenomegaly shows macrophages packed with tiny oval bodies, each with a nucleus and a rod-shaped kinetoplast. These are:
The kinetoplast next to the nucleus identifies Leishmania amastigotes (Leishman-Donovan bodies) of visceral leishmaniasis. Histoplasma yeasts lack a kinetoplast.
Compared with myeloblasts, typical lymphoblasts show:
Lymphoblasts usually have a high N:C ratio, scant agranular blue cytoplasm and inconspicuous nucleoli. Myeloblasts more often show more cytoplasm, prominent nucleoli and sometimes granules or Auer rods.
A patient has primary adrenal insufficiency with hypotension, hyponatremia and hyperkalemia. Which leukocyte change fits best?
Cortisol normally lowers eosinophil counts; in adrenal insufficiency the lack of cortisol leads to eosinophilia and relative lymphocytosis. Toxic neutrophilia suggests infection.
An unvaccinated infant with paroxysmal cough has WBC 45 × 10^9/L, mostly small mature lymphocytes, some with cleaved nuclei. The most likely cause is:
Pertussis toxin causes a marked absolute lymphocytosis of small mature (often cleaved) lymphocytes. ALL shows blasts, and infectious mononucleosis shows large reactive lymphocytes.
A patient has WBC 0.8 × 10^9/L and a differential is needed. The best way to find enough cells is:
Buffy coat smears concentrate leukocytes from centrifuged blood, allowing a meaningful differential in severe leukopenia. The thick part of a smear has distorted, overlapping cells.
The normal myeloid-to-erythroid (M:E) ratio in adult bone marrow is about:
Myeloid precursors normally outnumber erythroid precursors about 2–4 to 1. A low ratio suggests erythroid hyperplasia (e.g., hemolysis) or reduced myelopoiesis.
A cancer patient receiving G-CSF has WBC 35 × 10^9/L with toxic granulation, Döhle bodies and a few myelocytes. The best interpretation is:
G-CSF stimulates neutrophil production and release, giving neutrophilia, left shift and toxic changes that mimic infection. A history of growth factor use avoids misinterpretation.
A 'basket' or smudge cell differs from a necrobiotic neutrophil because the smudge cell:
Smudge cells are fragile cells broken during smear making, leaving only a spread-out nucleus. Apoptotic (necrobiotic) neutrophils keep cytoplasm with dense, round, pyknotic nuclear pieces.
Which pair of antigens is most useful for recognizing monocytes by flow cytometry?
Mature monocytes express CD14 and CD64 with CD11b and HLA-DR. CD3/CD7 are T-cell antigens, CD19/CD20 B-cell and CD41/CD61 platelet antigens.
Myeloperoxidase in neutrophils is found in which granules?
Myeloperoxidase is a marker enzyme of the primary (azurophilic) granules, which first appear at the promyelocyte stage.
A WBC count is 3.0 × 10^9/L with 60% lymphocytes, giving an absolute lymphocyte count of 1.8 × 10^9/L. The best description is:
The lymphocyte percentage is high, but the absolute count (1.8 × 10^9/L) is within the adult reference range. So this is a relative lymphocytosis, usually due to low neutrophils.