MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 12
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
Intrinsic factor, needed for vitamin B12 absorption, is secreted by which cells?
Parietal cells of the stomach secrete both hydrochloric acid and intrinsic factor. Chief cells secrete pepsinogen, and the ileum is where the B12–intrinsic factor complex is absorbed.
Dietary folate is absorbed mainly in which part of the gut?
Folate is absorbed in the proximal small intestine (duodenum and jejunum). The terminal ileum is the site of vitamin B12 absorption.
Hepcidin, the hormone that controls iron absorption and release, is produced mainly by the:
Hepcidin is made by hepatocytes. It blocks ferroportin, reducing iron absorption from the gut and iron release from macrophages.
Which pattern of red cell indices describes a microcytic hypochromic anemia?
Microcytic means a low MCV (small cells) and hypochromic means low hemoglobin per cell, shown by a low MCH (and often low MCHC). Iron deficiency is the classic example.
Enlarged infected red cells with fine pink-red stippling (Schüffner dots) on a Giemsa-stained thin film suggest infection with:
Schüffner dots in enlarged red cells are typical of P. vivax (P. ovale shows similar dots). P. falciparum shows Maurer clefts, and P. malariae infects normal-sized cells without Schüffner dots.
A red cell containing iron granules (Pappenheimer bodies) that stain with Prussian blue is called a:
A siderocyte is a red cell that contains iron-positive granules. Spherocytes, stomatocytes and schistocytes are shape changes.
A white cell slightly larger than a red cell, with a round dense nucleus and a thin rim of sky-blue cytoplasm, is a:
This is the typical small lymphocyte. Monocytes are much larger with folded nuclei, and neutrophils and basophils have lobed nuclei and granules.
The movement of neutrophils out of blood vessels, squeezing between endothelial cells into the tissues, is called:
Diapedesis is the passage of leukocytes through the vessel wall. Chemotaxis is directed movement toward chemical signals, and margination is sticking to the vessel wall.
Infectious mononucleosis is caused by which virus?
Classic infectious mononucleosis is caused by Epstein-Barr virus, which infects B lymphocytes. The heterophile (Monospot) test supports the diagnosis.
Acute promyelocytic leukemia is characterized by which translocation?
APL carries t(15;17), which forms the PML::RARA fusion. t(9;22) is the Philadelphia chromosome, t(8;14) is typical of Burkitt lymphoma and t(14;18) of follicular lymphoma.
Acute leukemia is best described as:
In acute leukemia, maturation is blocked and blasts build up quickly, crowding out normal blood cell production. A slow rise of mature lymphocytes describes CLL.
Which description fits a normal platelet on a Wright-stained smear?
Platelets have no nucleus. They are fragments of megakaryocyte cytoplasm with purple-staining granules.
During platelet aggregation, fibrinogen forms bridges between platelets by binding to which receptor?
Activated GP IIb/IIIa (integrin αIIbβ3) binds fibrinogen, linking platelets together. GP Ib/IX/V binds von Willebrand factor for adhesion, and P2Y12 is an ADP receptor.
Primary hemostasis ends with the formation of:
Primary hemostasis is vessel constriction plus platelet adhesion and aggregation, forming a platelet plug. Secondary hemostasis (coagulation) then adds a stable fibrin mesh.
Coagulation factor IV is:
Factor IV is calcium, which several clotting complexes need. Citrate and EDTA prevent clotting by removing it. Proaccelerin is factor V.
Which enzyme breaks down fibrin in a clot?
Plasmin, formed from plasminogen by tissue plasminogen activator, digests fibrin. Thrombin forms fibrin, and factor XIIIa cross-links it.
Which drug is given to reverse an overdose of unfractionated heparin?
Protamine sulfate binds heparin and neutralizes it. Vitamin K reverses warfarin, and tranexamic acid inhibits fibrinolysis.
The first response of a blood vessel to injury is:
Injured vessels constrict at once to reduce blood flow. Platelet plug formation and coagulation follow, and fibrinolysis comes last.
Which drug is an iron chelator used in transfusion-dependent thalassemia?
Deferoxamine (and oral agents such as deferasirox) binds excess iron so it can be excreted, preventing damage from transfusional iron overload.
The most common type of crisis in sickle cell disease is:
Painful vaso-occlusive crises, caused by sickled cells blocking small vessels, are by far the most common. The other crises are less frequent but can be severe.