Clinical Sciences Flashcards
7 cards from real STP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Clinical Sciences flashcards as text
A 25-year-old woman has a positive lupus anticoagulant, elevated anti-cardiolipin IgG, and a history of recurrent miscarriages. Her APTT does not correct on 1:1 mixing. Which diagnosis is most consistent?
Answer: Antiphospholipid syndrome
Antiphospholipid syndrome is characterized by antiphospholipid antibodies (lupus anticoagulant, anti-cardiolipin) causing thrombosis and pregnancy morbidity, with non-correcting APTT confirming an inhibitor.
In the context of clinical pharmacology, which pharmacokinetic parameter describes the volume of fluid required to contain all of the drug in the body at the observed plasma concentration?
Answer: Volume of distribution
Volume of distribution (Vd) is a theoretical volume that relates total drug in the body to plasma concentration; a high Vd indicates extensive tissue distribution.
A patient has sodium 128 mmol/L, urine osmolality 520 mOsm/kg, urine sodium 55 mmol/L, and normal thyroid/adrenal function. Which condition best explains these findings?
Answer: SIADH
SIADH presents with euvolemic hyponatremia, inappropriately elevated urine osmolality (>100 mOsm/kg), and elevated urine sodium (>20 mmol/L) with normal thyroid and adrenal function.
Which PCR technique allows simultaneous quantification of multiple target sequences in a single reaction by using different fluorescent probes?
Answer: Multiplex real-time PCR
Multiplex real-time PCR uses multiple primer pairs and fluorescent probes with distinct emission wavelengths to simultaneously detect and quantify several targets in one reaction.
In immunohistochemistry, heat-induced epitope retrieval (HIER) is used primarily to overcome which problem?
Answer: Antigen masking by formalin cross-links
Formalin fixation creates protein cross-links that mask antigenic epitopes; HIER uses heat and buffer to break these cross-links and restore antigen-antibody binding capacity.
A newborn screening program detects elevated phenylalanine on a dried blood spot at day 5. Which metabolic disorder must be excluded first?
Answer: Phenylketonuria (PKU)
Elevated phenylalanine on newborn dried blood spot screening is the primary marker for PKU, caused by phenylalanine hydroxylase deficiency, requiring prompt dietary intervention to prevent intellectual disability.
Which haematological finding on peripheral blood film is characteristic of hyposplenism?
Answer: Howell-Jolly bodies and target cells
Howell-Jolly bodies (nuclear remnants) and target cells are characteristic of hyposplenism, as the spleen normally removes these erythrocyte inclusions; their persistence indicates splenic dysfunction.