MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 15
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
Which of these plasma proteins is made by plasma cells rather than by the liver?
Immunoglobulins are produced by plasma cells. Albumin, fibrinogen and transferrin are synthesised by hepatocytes.
Which serum enzyme rises most characteristically when bile flow is obstructed (cholestasis)?
Cholestasis stimulates synthesis of ALP by bile duct cells, so ALP (with GGT) rises markedly. CK is a muscle enzyme and amylase a pancreatic/salivary enzyme.
In physiological jaundice of the newborn, which bilirubin fraction is mainly increased?
Newborns have immature UDP-glucuronyltransferase and a high red cell turnover, so unconjugated bilirubin accumulates.
What is the basic functional unit of the kidney?
The nephron, made up of the glomerulus and its tubule, is the functional unit that filters blood and forms urine.
To calculate creatinine clearance, which specimens are needed?
Clearance = (urine creatinine × urine volume per minute) ÷ plasma creatinine, so both a timed urine collection and a plasma or serum creatinine are required.
Which ion is the main cation of the extracellular fluid?
Sodium is the dominant extracellular cation (about 135–145 mmol/L in plasma). Potassium is the main intracellular cation.
In adults, hyponatremia is usually defined as a serum sodium below about:
The adult reference interval for sodium is about 135–145 mmol/L, so values below 135 mmol/L are hyponatremia.
Which thyroid hormone is secreted in the largest amount by the thyroid gland?
The thyroid secretes mainly T4; most circulating T3 is formed from T4 in peripheral tissues. T3 is the more active hormone.
Cortisol is produced by the:
Cortisol is made in the zona fasciculata of the adrenal cortex under ACTH control. The adrenal medulla makes catecholamines.
Which hormone raises blood calcium?
PTH raises blood calcium by releasing calcium from bone, increasing renal reabsorption and stimulating calcitriol formation. Calcitonin lowers calcium.
Which of these hormones is a steroid?
Aldosterone is a steroid made from cholesterol in the adrenal cortex. Insulin and TSH are peptide/protein hormones and epinephrine is an amino acid (catecholamine) derivative.
In an adult, a serum ferritin below about 15 ng/mL (15 µg/L) indicates:
Serum ferritin reflects body iron stores, and a value below about 15 µg/L is highly specific for iron deficiency. Inflammation raises ferritin rather than lowering it.
Natural killer (NK) cells belong to which part of the immune system?
NK cells kill virus-infected and tumour cells without prior sensitisation and without antigen-specific receptors, so they are part of innate immunity.
Which part of an antibody molecule binds to Fc receptors on phagocytes?
The Fc region, formed by the constant domains of the heavy chains, binds Fc receptors and complement. The Fab region binds antigen.
Which is the largest secondary lymphoid organ in the body and filters blood?
The spleen is the largest secondary lymphoid organ; it filters blood, removes old red cells and mounts immune responses to blood-borne antigens.
The Widal test is used in the diagnosis of:
The Widal test detects agglutinating antibodies to Salmonella Typhi and Paratyphi O and H antigens in enteric fever.
Which specimen is most commonly used for antibody (serological) testing?
Most serological tests are performed on serum from clotted blood. Other fluids are used only for specific tests.
In a sandwich ELISA for an antigen, the colour produced is:
More antigen captures more enzyme-labelled detection antibody, so more colour develops. In competitive immunoassays the signal is inversely related to analyte.
A raised total serum IgE is most commonly associated with:
IgE mediates type I hypersensitivity, and total IgE is often raised in atopic conditions such as allergic asthma and eczema, as well as in helminth infections.
In pemphigus vulgaris, autoantibodies attack which structure in the skin?
Pemphigus antibodies target desmogleins, causing loss of adhesion between epidermal cells and fragile intraepidermal blisters. Bullous pemphigoid targets hemidesmosomes.