Chemical Pathology MCQs | MCQ Quiz | OmpathStudy Kenya

Question 1

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

Accepted Answer

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

Question 2

Which test is the most specific for liver function?

Accepted Answer

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.

Question 3

Which electrolyte is the most abundant cation in extracellular fluid?

Accepted Answer

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

Question 4

An increased anion gap metabolic acidosis can be caused by:

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

Which of the following is an adrenal hormone?

Accepted Answer

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

Question 7

In primary hypothyroidism, TSH levels are typically:

Accepted Answer

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

Question 8

Which hormone is most useful for diagnosing acromegaly?

Accepted Answer

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

Question 9

Which test is used to confirm Cushing's syndrome?

Accepted Answer

Low-dose dexamethasone suppression test — This test differentiates normal individuals (who suppress cortisol) from those with Cushing's syndrome (who fail to suppress).

Question 10

Which enzyme deficiency is most common in congenital adrenal hyperplasia?

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

A low fractional excretion of sodium (FENa) suggests:

Accepted Answer

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

Question 13

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

Accepted Answer

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

Question 14

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

Accepted Answer

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

Question 15

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

Accepted Answer

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

Question 16

Which liver enzyme is most specific for hepatocellular injury?

Accepted Answer

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.

Question 17

Which of the following is the best marker of cholestasis?

Accepted Answer

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

Question 18

Which lipoprotein is primarily responsible for transporting cholesterol to tissues?

Accepted Answer

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

Question 19

Familial hypercholesterolemia is caused by a defect in which receptor?

Accepted Answer

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

Question 20

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

Accepted Answer

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

Question 21

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

Accepted Answer

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.

Question 22

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

Accepted Answer

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

Question 23

Which tumor marker is most specific for hepatocellular carcinoma?

Accepted Answer

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

Question 24

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

Accepted Answer

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

Question 25

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

Accepted Answer

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

Question 26

Which of the following is a primary metabolic alkalosis?

Accepted Answer

Vomiting — Vomiting causes loss of gastric acid (HCl), leading to metabolic alkalosis. COPD causes respiratory acidosis.

Question 27

A patient with a pH of 7.25, PaCO₂ of 60 mmHg, and HCO₃⁻ of 24 mEq/L has:

Accepted Answer

Respiratory acidosis — pH <7.35 with elevated PaCO₂ ( 45 mmHg) indicates respiratory acidosis. Normal bicarbonate suggests acute condition.

Question 28

Which of the following causes a normal anion gap metabolic acidosis?

Accepted Answer

Renal tubular acidosis — RTA causes normal anion gap acidosis due to impaired renal acid excretion. Other options cause high anion gap acidosis.

Question 29

A patient with metabolic acidosis and an increased anion gap likely has:

Accepted Answer

Diabetic ketoacidosis — DKA produces ketoacids, causing high anion gap metabolic acidosis. RTA causes normal anion gap acidosis.

Question 30

Which compensatory response occurs in metabolic acidosis?

Accepted Answer

Increased respiratory rate — Metabolic acidosis triggers hyperventilation to blow off CO₂ and partially compensate for the acidosis. ## Case-Based MCQs Section 1: Electrolytes & Acid-Base Disorders

Question 31

A 65-year-old man with chronic kidney disease presents with weakness and palpitations. ECG shows peaked T waves. Lab results: K⁺ 6.5 mmol/L, Na⁺ 140 mmol/L, BUN 55 mg/dL, Creatinine 4.2 mg/dL. What is the next best step?

Accepted Answer

IV calcium gluconate — Severe hyperkalemia with ECG changes (peaked T waves) is a cardiac emergency. IV calcium stabilizes cardiac membrane first.

Question 32

A 50-year-old woman with severe vomiting for three days presents with muscle cramps and weakness. Lab results: Na⁺ 138 mmol/L, K⁺ 2.8 mmol/L, Cl⁻ 85 mmol/L, HCO₃⁻ 34 mmol/L. What is the acid-base disorder?

Accepted Answer

Metabolic alkalosis — High bicarbonate (34 mmol/L) with hypokalemia and hypochloremia from vomiting indicates metabolic alkalosis.

Question 33

A 35-year-old diabetic man presents with confusion and deep rapid breathing. Blood gas: pH 7.1, PaCO₂ 22 mmHg, HCO₃⁻ 10 mmol/L, glucose 550 mg/dL. What is the primary acid-base disorder?

Accepted Answer

Metabolic acidosis — Low pH (7.1) with low bicarbonate (10) and compensatory hyperventilation (low CO₂) indicates metabolic acidosis from DKA.

Question 34

A 72-year-old man with COPD presents with confusion. Blood gas: pH 7.28, PaCO₂ 60 mmHg, HCO₃⁻ 28 mmol/L. What is the most likely acid-base disorder?

Accepted Answer

Respiratory acidosis — Low pH with high CO₂ indicates respiratory acidosis. Elevated bicarbonate suggests chronic compensation.

Question 35

A 45-year-old woman with chronic diarrhea presents with weakness. Labs: Na⁺ 138 mmol/L, K⁺ 3.0 mmol/L, Cl⁻ 105 mmol/L, HCO₃⁻ 15 mmol/L. What is the likely diagnosis?

Accepted Answer

Normal anion gap metabolic acidosis — Anion gap = 138 - (105 + 15) = 18 (normal range). Diarrhea causes bicarbonate loss leading to normal anion gap acidosis. ## Case-Based MCQs Section 2: Kidney Function & Renal Pathology

Question 36

A 55-year-old hypertensive patient presents with swelling and decreased urine output. Labs: BUN 45 mg/dL, Creatinine 3.8 mg/dL, Na⁺ 134 mmol/L, K⁺ 5.2 mmol/L. Urine Na⁺ <10 mmol/L, Urine osmolality 500 mOsm/kg. What is the likely cause?

Accepted Answer

Prerenal azotemia — Low urine sodium (<20) and high urine osmolality ( 500) indicate intact tubular function trying to conserve sodium and water.

Question 37

A 70-year-old diabetic patient presents with chronic kidney disease. Labs: BUN 55 mg/dL, Creatinine 5.5 mg/dL, eGFR 15 mL/min. What stage of CKD is this?

Accepted Answer

Stage 5 Correct — eGFR <15 mL/min indicates Stage 5 CKD (kidney failure), requiring renal replacement therapy consideration.

Question 38

A patient with nephrotic syndrome has edema and proteinuria 3.5 g/day. What is the most likely biochemical abnormality?

Accepted Answer

Hypoalbuminemia — Massive proteinuria in nephrotic syndrome leads to hypoalbuminemia, causing decreased oncotic pressure and edema.

Question 39

A patient with acute tubular necrosis (ATN) will have:

Accepted Answer

Muddy brown casts — Muddy brown casts are pathognomonic for ATN, indicating tubular epithelial cell sloughing.

Question 40

A patient with SIADH will most likely have which lab finding?

Accepted Answer

Hyponatremia — SIADH causes excessive water retention, leading to dilutional hyponatremia with concentrated urine. ## Case-Based MCQs Section 3: Endocrine Disorders

Question 41

A 60-year-old man presents with weight gain, moon facies, and hypertension. Labs: Cortisol remains high after low-dose dexamethasone suppression test. What is the likely diagnosis?

Accepted Answer

Cushing's syndrome — Failure to suppress cortisol with low-dose dexamethasone confirms Cushing's syndrome. Clinical features support this diagnosis.

Question 42

A 25-year-old woman presents with palpitations, weight loss, and sweating. Labs: TSH <0.1 mIU/L, Free T4 high. What is the most likely diagnosis?

Accepted Answer

Hyperthyroidism — Suppressed TSH with elevated T4 and classic hyperthyroid symptoms confirms hyperthyroidism.

Question 43

A 30-year-old woman presents with fatigue, hypotension, and hyperpigmentation. Labs: Na⁺ 129 mmol/L, K⁺ 5.8 mmol/L, Cortisol low. What is the likely diagnosis?

Accepted Answer

Addison's disease — Low cortisol with hyponatremia, hyperkalemia, and hyperpigmentation are classic for primary adrenal insufficiency (Addison's disease).

Question 44

A patient with secondary hyperparathyroidism due to chronic kidney disease will have:

Accepted Answer

High PTH — CKD causes phosphate retention and vitamin D deficiency, leading to low/normal calcium and compensatory PTH elevation.

Question 45

Which of the following conditions is most commonly associated with hypercalcemia?

Accepted Answer

Hyperparathyroidism — Primary hyperparathyroidism is the most common cause of hypercalcemia in outpatients, followed by malignancy in hospitalized patients. ## Case-Based MCQs Section 4: Diabetes & Glucose Disorders

Question 46

A 40-year-old man with polyuria and polydipsia has fasting glucose of 150 mg/dL and HbA1c of 8.5%. What is the diagnosis?

Accepted Answer

Diabetes mellitus — Fasting glucose ≥126 mg/dL and HbA1c ≥6.5% both meet criteria for diabetes mellitus diagnosis.

Question 47

A patient presents with altered mental status and blood glucose of 35 mg/dL. What is the most likely cause?

Accepted Answer

Insulinoma — Severe hypoglycemia (35 mg/dL) with altered mental status suggests insulin excess, most likely from an insulinoma.

Question 48

A 65-year-old diabetic patient with non-healing ulcers likely has:

Accepted Answer

Hyperglycemia-induced vascular damage — Chronic hyperglycemia causes microvascular and macrovascular complications, leading to poor wound healing.

Question 49

Which test is most useful for long-term diabetes monitoring?

Accepted Answer

HbA1c — HbA1c reflects average glucose over 2-3 months, making it ideal for long-term diabetes monitoring and management.

Question 50

A diabetic patient with nausea, abdominal pain, and high blood glucose should be evaluated for:

Accepted Answer

Diabetic ketoacidosis — Nausea, abdominal pain with hyperglycemia in a diabetic patient suggests DKA, especially with ketosis and acidosis. ## Chemical Pathology Calculations Section

Chemical Pathology MCQs | MCQ Quiz | OmpathStudy Kenya

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