Chemical Pathology MCQs – 83 MCQs | Kenya MBChB

83 Year 3: Endocrine and Metabolic Pathology exam questions on Chemical Pathology MCQs for medical students. Includes MCQs, answers, explanations and written qu

This MCQ set contains 83 questions on Chemical Pathology MCQs in the Year 3: Endocrine and Metabolic Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: Which of the following is NOT measured in a basic metabolic panel (BMP)?

  1. A. Glucose
  2. B. Creatinine
  3. C. Bilirubin
  4. D. Sodium Correct

Correct answer: C – Bilirubin

A BMP typically includes glucose, electrolytes (Na+, K+, Cl-, CO2), BUN, and creatinine. Bilirubin is part of liver function tests, not the BMP.

Q2: Which test is the most specific for liver function?

  1. A. ALT
  2. B. AST
  3. C. ALP
  4. D. GGT Correct

Correct answer: A – ALT

ALT (Alanine aminotransferase) is more specific for hepatocellular injury as it's primarily found in the liver, while AST is found in multiple organs including heart and muscle.

Q3: Which electrolyte is the most abundant cation in extracellular fluid?

  1. A. Sodium
  2. B. Potassium
  3. C. Calcium
  4. D. Magnesium Correct

Correct answer: A – Sodium

Sodium (Na+) is the predominant cation in extracellular fluid (normal: 135-145 mEq/L), while potassium is the main intracellular cation.

Q4: An increased anion gap metabolic acidosis can be caused by:

  1. A. Diarrhea
  2. B. Lactic acidosis
  3. C. Renal tubular acidosis
  4. D. Hyperaldosteronism Correct

Correct answer: B – Lactic acidosis

Lactic acidosis causes increased anion gap metabolic acidosis due to organic acid accumulation. Diarrhea and RTA typically cause normal anion gap acidosis.

Q5: Which analyte is most useful in the diagnosis of multiple myeloma?

  1. A. Serum iron
  2. B. Beta-2 microglobulin
  3. C. Serum protein electrophoresis
  4. D. Alkaline phosphatase Correct

Correct answer: C – Serum protein electrophoresis

SPEP detects monoclonal proteins (M-proteins) characteristic of multiple myeloma, showing abnormal immunoglobulin bands. Section 2: Endocrine Disorders & Hormone Assays

Q6: Which of the following is an adrenal hormone?

  1. A. T3
  2. B. Cortisol
  3. C. Prolactin
  4. D. ADH Correct

Correct answer: B – Cortisol

Cortisol is produced by the adrenal cortex. T3 is thyroid hormone, prolactin is pituitary hormone, and ADH is produced by the hypothalamus.

Q7: In primary hypothyroidism, TSH levels are typically:

  1. A. High
  2. B. Low
  3. C. Normal
  4. D. Undetectable Correct

Correct answer: A – High

Primary hypothyroidism involves thyroid gland failure, so TSH is elevated due to loss of negative feedback from low thyroid hormones.

Q8: Which hormone is most useful for diagnosing acromegaly?

  1. A. Cortisol
  2. B. Growth hormone
  3. C. IGF-1
  4. D. ACTH Correct

Correct answer: C – IGF-1

IGF-1 is more stable than GH and better reflects long-term GH secretion, making it the preferred screening test for acromegaly.

Q9: Which test is used to confirm Cushing's syndrome?

  1. A. Serum cortisol at 8 AM
  2. B. Low-dose dexamethasone suppression test
  3. C. Serum ACTH
  4. D. 24-hour urine free cortisol Correct

Correct answer: B – Low-dose dexamethasone suppression test

This test differentiates normal individuals (who suppress cortisol) from those with Cushing's syndrome (who fail to suppress).

Q10: Which enzyme deficiency is most common in congenital adrenal hyperplasia?

  1. A. 21-hydroxylase
  2. B. 17-hydroxylase
  3. C. 11β-hydroxylase
  4. D. 5α-reductase Correct

Correct answer: A – 21-hydroxylase

21-hydroxylase deficiency accounts for ~95% of CAH cases, leading to cortisol deficiency and androgen excess. Section 3: Kidney Function & Electrolytes

Q11: The best marker for glomerular filtration rate (GFR) is:

  1. A. Serum creatinine
  2. B. Blood urea nitrogen (BUN)
  3. C. Creatinine clearance
  4. D. Serum cystatin C Correct
  5. E. Serum cystatin C

Correct answer: D – Serum cystatin C Correct

Cystatin C is less affected by muscle mass, age, and diet compared to creatinine, providing a more accurate GFR assessment.

Q12: A low fractional excretion of sodium (FENa) suggests:

  1. A. Acute tubular necrosis
  2. B. Prerenal azotemia
  3. C. Hyperkalemia
  4. D. Hypocalcemia Correct

Correct answer: B – Prerenal azotemia

FENa <1% indicates intact tubular function with appropriate sodium retention, typical of prerenal causes of AKI.

Q13: Which electrolyte abnormality is associated with ECG changes such as peaked T waves?

  1. A. Hypocalcemia
  2. B. Hyperkalemia
  3. C. Hypernatremia
  4. D. Hypomagnesemia Correct

Correct answer: B – Hyperkalemia

Hyperkalemia causes characteristic ECG changes: peaked T waves, widened QRS, and can progress to sine waves and cardiac arrest.

Q14: Which acid-base disorder is commonly seen in patients with chronic kidney disease?

  1. A. Metabolic acidosis
  2. B. Metabolic alkalosis
  3. C. Respiratory acidosis
  4. D. Respiratory alkalosis Correct

Correct answer: A – Metabolic acidosis

CKD causes metabolic acidosis due to decreased acid excretion, reduced ammonia production, and bicarbonate loss.

Q15: Which of the following conditions leads to an increased BUN-to-creatinine ratio?

  1. A. Liver failure
  2. B. SIADH
  3. C. Prerenal azotemia
  4. D. Rhabdomyolysis Correct

Correct answer: C – Prerenal azotemia

Prerenal azotemia increases BUN more than creatinine due to enhanced urea reabsorption, raising the BUN:Cr ratio 20:1. Section 4: Liver Function & Lipid Metabolism

Q16: Which liver enzyme is most specific for hepatocellular injury?

  1. A. ALP
  2. B. AST
  3. C. ALT
  4. D. GGT Correct

Correct answer: C – ALT

ALT is predominantly found in hepatocytes, making it more specific for liver injury than AST, which is also found in cardiac and skeletal muscle.

Q17: Which of the following is the best marker of cholestasis?

  1. A. ALT
  2. B. ALP
  3. C. Bilirubin
  4. D. Ammonia Correct

Correct answer: B – ALP

Alkaline phosphatase is elevated in cholestatic conditions due to increased synthesis and release from bile duct epithelium.

Q18: Which lipoprotein is primarily responsible for transporting cholesterol to tissues?

  1. A. HDL
  2. B. LDL
  3. C. VLDL
  4. D. Chylomicrons Correct

Correct answer: B – LDL

LDL carries cholesterol from liver to peripheral tissues and is the major atherogenic lipoprotein.

Q19: Familial hypercholesterolemia is caused by a defect in which receptor?

  1. A. LDL receptor
  2. B. VLDL receptor
  3. C. Apolipoprotein A-I
  4. D. CETP Correct

Correct answer: A – LDL receptor

FH is caused by mutations in the LDL receptor gene, leading to impaired cholesterol uptake and very high LDL levels.

Q20: A fasting glucose level of 8.0 mmol/L (144 mg/dL) suggests:

  1. A. Normal glucose metabolism
  2. B. Prediabetes
  3. C. Diabetes mellitus
  4. D. Hypoglycemia Correct

Correct answer: C – Diabetes mellitus

Fasting glucose ≥7.0 mmol/L (126 mg/dL) indicates diabetes mellitus. 144 mg/dL clearly meets this criterion. Section 5: Tumor Markers & Cancer Screening

Q21: Which tumor marker is most commonly used for ovarian cancer screening?

  1. A. CA 15-3
  2. B. CA 125
  3. C. PSA
  4. D. CEA Correct

Correct answer: B – CA 125

CA 125 is the most widely used tumor marker for ovarian cancer, though it's not specific and can be elevated in benign conditions.

Q22: A patient with suspected pancreatic cancer is likely to have elevated levels of:

  1. A. AFP
  2. B. CA 19-9
  3. C. CEA
  4. D. Beta-2 microglobulin Correct

Correct answer: B – CA 19-9

CA 19-9 is the most useful tumor marker for pancreatic adenocarcinoma, though it's also elevated in biliary obstruction.

Q23: Which tumor marker is most specific for hepatocellular carcinoma?

  1. A. CA 19-9
  2. B. AFP
  3. C. PSA
  4. D. CA 15-3 Correct

Correct answer: B – AFP

Alpha-fetoprotein (AFP) is the most specific tumor marker for hepatocellular carcinoma, though it can also be elevated in other liver diseases.

Q24: A patient with an enlarged prostate and elevated PSA should undergo:

  1. A. Serum testosterone
  2. B. Prostate biopsy
  3. C. Bone scan
  4. D. CT scan Correct

Correct answer: B – Prostate biopsy

Elevated PSA with enlarged prostate requires tissue diagnosis via biopsy to rule out prostate cancer.

Q25: The presence of high levels of CEA is most suggestive of:

  1. A. Breast cancer
  2. B. Colorectal cancer
  3. C. Prostate cancer
  4. D. Ovarian cancer Correct

Correct answer: B – Colorectal cancer

CEA (carcinoembryonic antigen) is most commonly associated with colorectal cancer, though it's not specific. Section 6: Acid-Base Disorders & Blood Gases

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