ABPath Clinical Pathology 3 — Questions and Answers
Question 1: Which blood group antibody is most commonly associated with severe hemolytic disease of the fetus and newborn?
- Anti-D (Correct answer)
- Anti-Lewis
- Anti-M
- Anti-P1
Correct answer: Anti-D
Anti-D is an IgG antibody that readily crosses the placenta and causes severe HDFN.
Question 2: A positive direct antiglobulin test (DAT) with C3d only and cold agglutinins is most consistent with:
- Cold agglutinin disease (Correct answer)
- Warm autoimmune hemolytic anemia
- Drug-induced hemolysis
- Paroxysmal nocturnal hemoglobinuria
Correct answer: Cold agglutinin disease
Cold agglutinin disease typically shows complement (C3d) coating without IgG on the DAT.
Question 3: Which urine finding best supports a diagnosis of acute tubular necrosis rather than prerenal azotemia?
- Muddy brown granular casts (Correct answer)
- Hyaline casts
- RBC casts
- WBC casts
Correct answer: Muddy brown granular casts
Muddy brown granular casts (renal tubular epithelial casts) are characteristic of acute tubular necrosis.
Question 4: Which cerebrospinal fluid profile is most typical of bacterial meningitis?
- High neutrophils, low glucose, high protein (Correct answer)
- High lymphocytes, normal glucose, mildly high protein
- Normal cells, normal glucose, normal protein
- High eosinophils, normal glucose
Correct answer: High neutrophils, low glucose, high protein
Bacterial meningitis classically shows neutrophilic pleocytosis, hypoglycorrhachia, and elevated protein.
Question 5: Which enzyme elevation is most specific for myocardial injury?
- Cardiac troponin (Correct answer)
- Total creatine kinase
- AST
- LDH
Correct answer: Cardiac troponin
Cardiac troponin I and T are the most sensitive and specific markers of myocardial injury.
Question 6: A synovial fluid showing negatively birefringent needle-shaped crystals under polarized light indicates:
- Gout (monosodium urate) (Correct answer)
- Pseudogout (CPPD)
- Hydroxyapatite deposition
- Cholesterol crystals
Correct answer: Gout (monosodium urate)
Monosodium urate crystals are needle-shaped and negatively birefringent, diagnostic of gout.
Question 7: Which condition produces a spuriously low measured sodium due to hyperlipidemia or hyperproteinemia when using indirect ISE?
- Pseudohyponatremia (Correct answer)
- True hypovolemic hyponatremia
- SIADH
- Cerebral salt wasting
Correct answer: Pseudohyponatremia
Pseudohyponatremia occurs when excess lipids or proteins displace plasma water, lowering indirect ISE sodium readings.
ABPath Clinical Pathology 3
Which blood group antibody is most commonly associated with severe hemolytic disease of the fetus and newborn?