MLT GlobeMOH exam preparation (UAE) – page 4
700 practice MCQs for the MOH medical laboratory exam. Level: Basic to intermediate.
A child with heavy hookworm infection is likely to show which leukocyte change on the differential?
Tissue-invasive helminths drive IL-5 production, raising eosinophil counts. Hookworm may also cause iron deficiency anemia, but eosinophilia is the typical leukocyte change.
Which red cell index expresses average cell size, with a typical adult range of about 80–100 fL?
Mean cell volume in femtolitres classifies anemias as micro-, normo- or macrocytic. MCH is picograms per cell; RDW shows variation in size.
Which red cell index reports average hemoglobin mass per cell, typically about 27–33 pg?
Mean cell hemoglobin is Hb divided by RBC count, expressed in picograms. MCHC is a concentration (g/dL) and MCV is volume (fL).
Which red cell index gives the average hemoglobin concentration within red cells, normally about 32–36 g/dL?
MCHC is Hb divided by hematocrit. A raised MCHC suggests spherocytes or interference such as cold agglutinins; low values accompany hypochromia.
Which condition lowers the platelet count by reducing marrow production?
Aplastic anemia is marrow failure causing pancytopenia, including thrombocytopenia. Iron deficiency and splenectomy often raise platelets; polycythemia vera may raise them too.
Around the middle of fetal life, which organ is the main site of blood cell production?
The hepatic phase dominates from about the second to sixth fetal month, before the marrow takes over late in gestation.
Which ABO/RhD type can receive red cells of any ABO/RhD type in an emergency, since it lacks anti-A, anti-B and anti-D?
AB RhD-positive recipients have no anti-A or anti-B and their red cells carry D, so they are called universal recipients. O RhD negative is the universal red cell donor.
A film shows red cells of many abnormal shapes, such as teardrops and fragments. What term describes this?
Poikilocytosis means variation in red cell shape. Anisocytosis refers to size variation; polychromasia to blue-grey young cells; hypochromia to pale cells.
A child with microcytic anemia and normal ferritin is suspected of β-thalassemia. Which test confirms the diagnosis?
HPLC or electrophoresis shows raised HbA2 and HbF typical of β-thalassemia. A CBC suggests the diagnosis but cannot confirm it.
Which microscope part collects light from the source and focuses it onto the specimen?
The substage condenser concentrates and directs light through the specimen. The objective and ocular magnify the image.
A leukocyte has 3–5 nuclear lobes and pale lilac cytoplasm with fine granules. What is it?
Segmented nucleus plus fine neutral granules identify the neutrophil. Basophils have coarse dark granules, monocytes a folded nucleus, lymphocytes a round nucleus.
Detection of the BCR::ABL1 fusion from t(9;22) is key to diagnosing which disorder?
The Philadelphia chromosome, t(9;22), produces BCR::ABL1 and defines CML. It can also occur in some ALL, but CML is the disease it characterizes.
Which laboratory test is used to monitor warfarin therapy?
Warfarin reduces vitamin K-dependent factors, and PT is most sensitive to factor VII; the INR standardizes PT across reagents. APTT is used for unfractionated heparin.
Which test is part of a routine coagulation screen?
A basic coagulation screen includes PT, APTT and often fibrinogen and thrombin time. ESR and WBC count assess inflammation; the indirect Coombs test is a blood bank test.
Which anemia is typically normocytic and normochromic?
Marrow failure reduces cell numbers without altering hemoglobin synthesis, giving normocytic indices (sometimes mildly macrocytic). Iron deficiency and thalassemia are microcytic; B12 deficiency is macrocytic.
Hemophilia A results from deficiency of which coagulation factor?
Hemophilia A is factor VIII deficiency; hemophilia B (Christmas disease) is factor IX deficiency. Factor VII deficiency prolongs PT, not APTT.
Which coagulation factor does NOT need vitamin K for its synthesis in functional form?
Vitamin K is needed for gamma-carboxylation of factors II, VII, IX and X and proteins C and S. Factor XI is not vitamin K-dependent.
Red cells with an enlarged area of central pallor, making them look pale, are described as what?
Hypochromia means reduced hemoglobin content, seen as central pallor over one third of the cell diameter, as in iron deficiency and thalassemia.
Which is the earliest morphologically recognizable cell in the granulocyte series?
Granulocyte maturation proceeds from myeloblast to promyelocyte, myelocyte, metamyelocyte, band and segmented cell.
Which is the last nucleated stage before the nucleus is extruded in red cell development?
The sequence is pronormoblast, basophilic, polychromatic and orthochromatic normoblast; the orthochromatic cell then extrudes its nucleus to become a reticulocyte.