MLT GlobeDHA exam preparation (Dubai) – page 3
700 practice MCQs for the DHA medical laboratory exam. Level: Basic to intermediate.
In chronic hemolysis or marrow fibrosis, which organ most commonly resumes blood cell production outside the marrow?
Extramedullary hematopoiesis occurs mainly in the liver and spleen, the fetal sites of blood formation, causing hepatosplenomegaly.
A patient with acute bacterial pneumonia has an absolute neutrophil count of 14 × 10^9/L. What term describes this?
Neutrophilia is an absolute neutrophil count above the reference interval. A leukemoid reaction implies an extreme count (often >50 × 10^9/L); right shift means hypersegmentation.
On a Romanowsky-stained film, neutrophils, eosinophils and basophils are told apart mainly by what?
Neutral (lilac), acidophilic (orange-red) and basophilic (dark purple) specific granules identify the three granulocytes; all have nuclei and overlap in size.
How many heme groups does one molecule of adult hemoglobin contain, and so how many O2 molecules can it bind?
Hemoglobin is a tetramer of four globin chains, each carrying one heme with ferrous iron, so one molecule binds up to four O2 molecules.
In an adult, which type of bone marrow actively produces blood cells?
Red marrow is hematopoietically active; yellow marrow is mainly fat but can revert under stress. Gelatinous change reflects starvation, not activity.
What is a typical reference interval for reticulocytes in a healthy adult?
Normal marrow output gives about 0.5–2.5% reticulocytes (roughly 25–100 × 10^9/L). Higher values indicate a response to hemolysis or bleeding.
Which red cells show a blue granular network after staining with new methylene blue?
Supravital dyes precipitate residual ribosomal RNA in young red cells as a reticulum. Mature erythrocytes have no RNA; pronormoblasts are nucleated marrow cells.
Which of these is the most common cause of iron deficiency anemia in adults?
Chronic loss, such as heavy menstruation or gastrointestinal bleeding, depletes iron stores. In men and postmenopausal women, a GI source must be looked for.
Vitamin B12 is also known by which name?
B12 contains cobalt and is called cobalamin. Thiamine is B1, riboflavin B2 and niacin B3.
Fanconi anemia is best described as which kind of anemia?
Fanconi anemia is an inherited DNA repair disorder causing marrow failure, often with skeletal anomalies. Chromosome breakage testing confirms it.
A patient with deep vein thrombosis suddenly becomes breathless with chest pain. Which complication is most likely?
A leg vein thrombus can break off and lodge in the pulmonary arteries. D-dimer and CT pulmonary angiography support the diagnosis.
Which surface marker is found on T lymphocytes but not on B lymphocytes?
CD3 is part of the T-cell receptor complex and identifies T cells. CD19, CD20 and CD79a are B-cell markers used in flow cytometry.
A leukocyte on a film has coarse dark purple granules that largely hide a lobed nucleus. What is it?
Basophils contain large dark granules of histamine and heparin that cover the nucleus. Lymphocytes are agranular; reticulocytes have no nucleus.
A film shows red cells of very different sizes, reflected in a raised RDW. What is this called?
Anisocytosis means variation in red cell size, which the analyzer shows as a raised RDW. Poikilocytosis refers to variation in shape.
At what temperature are platelet concentrates stored in the blood bank?
Refrigeration causes platelet activation and fast clearance after transfusion, so platelets are kept at room temperature on an agitator. Red cells are stored at 2–6 °C and plasma frozen.
In which age group is chronic lymphocytic leukemia most often diagnosed?
CLL is the most common leukemia in Western adults, with a median diagnosis age around 70; it is extremely rare in children, where ALL predominates.
Two parents both have sickle cell trait (HbAS). What is the chance that each child will have sickle cell anemia (HbSS)?
Sickle cell disease is autosomal recessive. Each carrier parent passes the HbS allele half the time, so each child has a 1 in 4 chance of HbSS.
Which blood finding is characteristic of chronic lymphocytic leukemia?
CLL requires at least 5 × 10^9/L clonal B lymphocytes, which are small and mature-looking. Blasts suggest acute leukemia.
After centrifuging anticoagulated blood, which cells settle at the bottom because of their highest density?
Red cells are the densest and form the bottom layer; leukocytes and platelets form the buffy coat above them, with plasma on top.
The D antigen tested in routine blood typing belongs to which blood group system?
D is the most immunogenic Rh antigen and decides RhD-positive or -negative status. ABO antigens are A and B; Kell and Duffy are separate systems.