MLT GlobeQCHP exam preparation (Qatar) – page 13
749 practice MCQs for the QCHP medical laboratory exam. Level: Intermediate.
Which tissue cell is functionally similar to the blood basophil?
Mast cells, like basophils, carry IgE receptors and release histamine. Kupffer cells are liver macrophages derived from monocytes.
A routine manual differential count classifies how many white cells?
A standard manual differential counts 100 white cells so that each cell type can be reported as a percentage.
A total white cell count below the reference interval (for example 2.5 × 10^9/L in an adult) is called:
Leukopenia is a low total white cell count. Leukocytosis is a raised count, and a leukemoid reaction is a very high reactive count.
Lymphomas are malignancies that arise mainly in:
Lymphomas are cancers of lymphocytes that usually form masses in lymph nodes or other lymphoid tissue, unlike leukemias, which start in the marrow.
'B symptoms' in lymphoma refer to:
B symptoms are unexplained fever, drenching night sweats and weight loss of more than 10% in 6 months. They matter for staging and prognosis.
The CD34 antigen on blasts is a marker of:
CD34 is found on hematopoietic stem and early progenitor cells and on many leukemic blasts. It is lost as cells mature.
Agranulocytosis refers to:
Agranulocytosis is a severe fall in neutrophils (granulocytes), often drug-induced. It carries a high risk of serious infection.
Pinpoint red spots in the skin caused by capillary bleeding in severe thrombocytopenia are called:
Petechiae are tiny (1–2 mm) pinpoint hemorrhages typical of platelet problems. Ecchymoses are larger bruises, and hemarthroses are joint bleeds seen in factor deficiencies.
The routine automated platelet count is performed on blood collected into which anticoagulant?
EDTA (lavender top) is the anticoagulant for CBC and platelet counts. Heparin can cause platelet clumping, and a clotted sample uses up platelets.
Unfractionated heparin therapy is commonly monitored with which test?
The aPTT is the traditional test for monitoring unfractionated heparin (anti-Xa assays are also used). The PT/INR monitors warfarin.
The specific antidote that restores the vitamin K–dependent factors in a patient on warfarin is:
Warfarin blocks vitamin K recycling. Giving vitamin K allows the liver to make functional factors II, VII, IX and X again.
In hemolytic anemia, which bilirubin fraction is mainly raised in serum?
Increased heme breakdown produces more unconjugated bilirubin than the liver can conjugate. Conjugated bilirubin rises mainly in liver or biliary disease.
Hemoglobin C results from replacing glutamic acid at position 6 of the beta chain with:
HbC has lysine at beta-6, while HbS has valine at the same position.
Hemoglobin E is most common in people from:
HbE is very common in Southeast Asia (for example Thailand, Cambodia and Laos) and nearby regions. HbC and HbS are more common in West Africa.
Sickle cell trait gives partial protection against:
People with HbAS are partly protected from severe falciparum malaria, which explains the high frequency of the HbS gene in malarial regions.
In the Westergren method, the ESR is read after:
The Westergren ESR is the height of the clear plasma column after the tube stands upright for 60 minutes, reported in mm/hour.
In fingerstick blood collection, the first drop of blood is wiped away because it:
The first drop contains tissue fluid (and may contain alcohol), which dilutes the sample and gives wrong counts.
How are the A and B alleles expressed when a person inherits both?
A and B are codominant, so both antigens are made and the person is group AB. The O allele is recessive (amorphic).
The Bombay (Oh) phenotype was first described in:
The Bombay phenotype was first found in 1952 in Bombay (now Mumbai), India. These people lack H antigen and make strong anti-H.
In tube agglutination grading, a single solid clump with a clear background is graded as:
4+ is one solid agglutinate with a clear background. Weaker grades show smaller clumps with a cloudy red background.