MLT GlobeQCHP exam preparation (Qatar) – page 23
749 practice MCQs for the QCHP medical laboratory exam. Level: Intermediate.
When classifying a neutrophil as a segmented form rather than a band, the key feature is:
A segmented neutrophil has lobes connected by a thin chromatin filament. A band has a curved nucleus of roughly even width without a filament.
A child with partial albinism and repeated pyogenic infections has neutrophils with huge, fused grey-red cytoplasmic granules. The most likely disorder is:
Chediak-Higashi syndrome (LYST mutation) shows giant fused lysosomal granules, oculocutaneous albinism and poor killing of bacteria. Alder-Reilly granules are small and dense, without infections.
Dark, coarse granules in neutrophils, lymphocytes and monocytes of a child with a mucopolysaccharidosis such as Hurler syndrome are called:
Alder-Reilly granules are partly digested mucopolysaccharides in all leukocyte types. Toxic granulation is confined to neutrophils and linked to infection.
Which feature best favors reactive lymphocytes over lymphoblasts on a smear?
Reactive lymphocytes form a heterogeneous population with varied size and cytoplasm. Blasts are monotonous, with fine chromatin, nucleoli and high N:C ratio.
Large granular lymphocytes with azurophilic cytoplasmic granules are most often:
LGLs are NK cells (CD16, CD56) or cytotoxic T cells (CD8, CD57); the granules contain perforin and granzymes. B cells and helper T cells lack these granules.
A cervical Pap shows squamous cells with sharply defined perinuclear cavities and enlarged, hyperchromatic, wrinkled nuclei (koilocytes). Using the Bethesda System, this is reported as:
Koilocytes represent HPV cytopathic effect and are classified as LSIL, which includes CIN 1. ASC-US is used when changes are only suggestive.
A cervical sample shows a few squamous cells with abnormalities that suggest, but are insufficient for, a high-grade lesion. The appropriate Bethesda category is:
ASC-H means atypical squamous cells, cannot exclude HSIL. ASC-US is used when the atypia suggests a low-grade change or its nature is unclear.
Paraffin infiltration baths are kept far above the wax melting point for many hours. The most likely effect on the tissue is:
Paraffin should be kept only about 2–4 °C above its melting point. Overheating makes tissue hard, brittle and shrunken, and damages antigens.
Sections show alternating thick and thin bands running parallel to the knife edge. This artifact is called:
Chatter results from vibration, often due to a loose blade or block, very hard or over-dehydrated tissue, or an incorrect clearance angle. Scoring runs perpendicular to the knife edge.
A bone biopsy left in strong acid decalcifier over the weekend is sectioned. What staining problem is most expected?
Over-decalcification in strong acid damages nucleic acids, so nuclei stain weakly and poorly with hematoxylin. Timely endpoint testing prevents this.
In regressive hematoxylin staining, tissue is:
Regressive staining deliberately overstains, then removes excess dye with acid alcohol. Progressive staining stains to the desired endpoint without differentiation.
A HEp-2 indirect immunofluorescence ANA shows discrete speckles (about 40–80 per interphase nucleus) that align on the chromosomes of metaphase cells. The associated antibody is:
The discrete speckled (centromere) pattern shows countable dots that line up on chromosomes in metaphase cells. It is associated with limited cutaneous systemic sclerosis (CREST).
A homogeneous ANA pattern with staining of the condensed chromosomes in mitotic cells is most associated with antibodies to:
Homogeneous nuclear staining with positive metaphase chromatin is typical of antibodies to dsDNA, histones and nucleosomes. SS-A and U1-RNP give speckled patterns with negative metaphase chromatin.
A patient has recurrent Neisseria meningitidis infections. Deficiency of which complement component is most likely?
Deficiency of terminal components (C5–C9) prevents formation of the membrane attack complex and predisposes to recurrent Neisseria infections. C1q and C2 deficiencies are more linked to lupus-like disease.
Class switching of B cells to produce IgE is mainly promoted by which cytokine?
IL-4 (and IL-13) from Th2 cells drives switching to IgE. Interferon-gamma and IL-12 favour Th1 responses and inhibit IgE production.
Toll-like receptor 4 (TLR4) on macrophages recognises which microbial molecule?
TLR4 binds lipopolysaccharide (endotoxin) of Gram-negative bacteria. TLR5 recognises flagellin, TLR3 double-stranded RNA and TLR9 CpG DNA.
A serum is tested in doubling dilutions starting at 1:2. Agglutination is seen in tubes 1 to 6 but not in tube 7. The titre is:
Tube 1 = 1:2, tube 2 = 1:4 ... tube 6 = 1:64. The titre is the reciprocal of the highest dilution with a positive reaction, so 64.
Immunofixation electrophoresis differs from protein electrophoresis because it:
After electrophoresis, specific antisera (anti-G, A, M, kappa, lambda) are applied to precipitate and type a monoclonal protein. It is more sensitive than serum protein electrophoresis for small bands.
In a competitive immunoassay, a higher concentration of analyte in the patient sample produces:
Patient analyte competes with labelled analyte for limited antibody. More patient analyte means less labelled analyte bound, so signal is inversely proportional to concentration.
A patient has HBsAg negative, anti-HBc total positive and anti-HBs positive. This pattern most likely indicates:
Anti-HBc shows past natural infection, and anti-HBs with negative HBsAg shows recovery and immunity. Vaccination produces anti-HBs alone without anti-HBc.