All Practice Exams
100+ Free CMSA FC Path(SA) Chemical Pathology Practice Questions
Fellowship of the College of Pathologists of South Africa — Chemical Pathology practice questions are available now; exam metadata is being verified.
✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately
100+ Questions
100% Free
Loading practice questions...
Same family resources
Explore More CMSA Fellowship Part I Examinations (South Africa)
Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.
Sample CMSA FC Path(SA) Chemical Pathology Practice Questions
Try these sample questions to test your CMSA FC Path(SA) Chemical Pathology exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1A 45-year-old male with severe diarrhoea presents with serum sodium 138 mmol/L, potassium 3.1 mmol/L, chloride 112 mmol/L, and bicarbonate 14 mmol/L. What is the serum anion gap in mmol/L?
A.8
B.12
C.16
D.20
Explanation: The serum anion gap is calculated as [Na+] − ([Cl-] + [HCO3-]). Substituting the given values: 138 − (112 + 14) = 138 − 126 = 12 mmol/L. A gap of about 12 mmol/L is normal and fits hyperchloraemic metabolic acidosis from gastrointestinal bicarbonate loss in severe diarrhoea.
2A 52-year-old man with type 2 diabetes presents with confusion. Serum sodium 128 mmol/L, glucose 38 mmol/L. Using the correction of 2.4 mmol/L per 10 mmol/L glucose above 5.6 mmol/L, what is the corrected sodium in mmol/L?
A.132
B.134
C.136
D.138
Explanation: Corrected Na+ = measured Na+ + 2.4 × (glucose − 5.6)/10 = 128 + 2.4 × 32.4/10 = 128 + 7.8 ≈ 136 mmol/L, indicating mild true hyponatraemia beyond pseudohyponatraemia from hyperglycaemia.
3A patient with ethylene glycol poisoning has serum sodium 140 mmol/L, glucose 5 mmol/L, urea 6 mmol/L, and measured serum osmolality 360 mOsm/kg. Estimated osmolality (2×Na + glucose + urea) is 292 mOsm/kg. What is the osmolal gap in mOsm/kg?
A.48
B.58
C.68
D.78
Explanation: Osmolal gap = measured osmolality − calculated osmolality = 360 − 292 = 68 mOsm/kg. An elevated osmolal gap (>10–15 mOsm/kg) with high anion gap metabolic acidosis suggests toxic alcohol ingestion.
4Arterial blood gas: pH 7.28, PaCO2 22 mmHg, HCO3− 10 mmol/L. Using Winter's formula, what is the expected PaCO2 (±2 mmHg)?
A.18–22 mmHg
B.22–26 mmHg
C.26–30 mmHg
D.30–34 mmHg
Explanation: Winter's formula: expected PaCO2 = 1.5 × [HCO3−] + 8 (±2) = 1.5 × 10 + 8 = 23 mmHg (range 21–25). Measured PaCO2 of 22 mmHg indicates appropriate respiratory compensation for primary metabolic acidosis.
5A patient with diabetic ketoacidosis has Na+ 140, Cl− 100, HCO3− 10 mmol/L. What is the serum anion gap in mmol/L?
A.20
B.24
C.28
D.30
Explanation: Anion gap = [Na+] − ([Cl−] + [HCO3−]) = 140 − 110 = 30 mmol/L, consistent with high anion gap metabolic acidosis in DKA.
6In metabolic acidosis, anion gap is 24 mmol/L (baseline 12) and bicarbonate fell from 24 to 12 mmol/L. What is the delta ratio (ΔAG/ΔHCO3−)?
A.0.5
B.1.0
C.1.5
D.2.0
Explanation: Delta ratio = (24−12)/(24−12) = 12/12 = 1.0, indicating pure high anion gap metabolic acidosis. Ratios <0.4 suggest concurrent normal AG acidosis; >2 suggest concurrent metabolic alkalosis.
7A 70-year-old on thiazides has Na+ 118 mmol/L, serum osmolality 250 mOsm/kg, urine osmolality 450 mOsm/kg. Which diagnosis is most likely?
A.Psychogenic polydipsia
B.SIADH
C.Diabetes insipidus
D.Addison disease
Explanation: Hyponatraemia with inappropriately concentrated urine (>100 mOsm/kg) in a euvolaemic patient suggests SIADH or thiazide-associated hyponatraemia. Psychogenic polydipsia causes dilute urine; DI causes hypernatraemia; Addison causes hyperkalaemia and volume depletion.
8Which finding best distinguishes renal tubular acidosis from diarrhoea as the cause of hyperchloraemic metabolic acidosis?
A.Urine pH >5.5 in type 1 RTA despite systemic acidosis
B.Urine anion gap >0 in diarrhoea
C.Urine potassium <20 mmol/L in all RTA types
D.Urine osmolality <100 mOsm/kg in RTA
Explanation: In distal (type 1) RTA, the kidney cannot acidify urine despite systemic acidosis (urine pH >5.5). In diarrhoea, appropriate renal acid excretion produces urine pH <5.5 and negative urine anion gap.
9A patient has potassium 6.8 mmol/L with peaked T waves. Which treatment lowers serum potassium fastest by intracellular shift?
A.Calcium gluconate IV
B.Insulin-dextrose infusion
C.Sodium polystyrene sulfonate
D.Calcium resonium enema
Explanation: Insulin with dextrose drives K+ intracellularly via Na+/K+-ATPase, producing the fastest reduction in extracellular K+. Calcium gluconate stabilises myocardium but does not lower K+. Resonium removes K+ via the gut over hours.
10Serum albumin 20 g/L, total calcium 1.95 mmol/L. Using correction (add 0.02 mmol/L per 1 g/L albumin below 40 g/L), what is corrected calcium in mmol/L?
A.2.15
B.2.25
C.2.35
D.2.45
Explanation: Corrected Ca = 1.95 + 0.02 × (40−20) = 1.95 + 0.40 = 2.35 mmol/L, revealing true hypocalcaemia masked by hypoalbuminaemia.
About the CMSA FC Path(SA) Chemical Pathology Practice Questions
Verified exam format metadata for Fellowship of the College of Pathologists of South Africa — Chemical Pathology is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.