1.Which of the following electrolytes is the primary extracellular cation?

A. Potassium
B. Sodium
C. Calcium
D. Magnesium

• ✅ Correct Answer: B. Sodium
• Sodium is the major extracellular cation, playing a crucial role in maintaining fluid balance, nerve transmission, and muscle function. While potassium is the main intracellular cation, sodium dominates outside the cells and is essential in osmotic pressure and acid-base balance.

2. Which enzyme is most commonly elevated in pancreatitis?

A. ALT
B. AST
C. Amylase
D. LDH

• ✅ Correct Answer: C. Amylase
• Amylase is an enzyme produced by the pancreas and salivary glands, and it is one of the first enzymes to rise in acute pancreatitis. It helps break down starches. Elevated levels in blood are a common indicator of pancreatic inflammation or injury.

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3. The normal reference range for serum potassium in adults is:

A. 2.5–3.5 mmol/L
B. 3.5–5.0 mmol/L
C. 5.5–7.0 mmol/L
D. 7.0–8.5 mmol/L

• ✅ Correct Answer: B. 3.5–5.0 mmol/L
• The normal reference range for serum potassium in adults is 3.5–5.0 mmol/L. Potassium is an essential intracellular cation that is crucial for muscle function, nerve transmission, and maintaining the resting membrane potential. Abnormal potassium levels can result in cardiac arrhythmias, muscle weakness, and other severe symptoms.

4. Which of the following is most likely to increase in the blood during obstructive jaundice?

A. Unconjugated bilirubin
B. Conjugated bilirubin
C. Urobilinogen
D. Serum albumin

• ✅ Correct Answer: B. Conjugated bilirubin
• In obstructive jaundice, bile flow is blocked, usually due to a gallstone or tumor in the bile ducts. As a result, conjugated bilirubin (the form of bilirubin processed in the liver) backs up into the bloodstream, leading to increased serum conjugated bilirubin levels. This causes yellowing of the skin and eyes (jaundice).

5. Which of the following is a primary cause of hyperglycemia in diabetic patients?

A. Increased insulin secretion
B. Decreased glucagon production
C. Insulin resistance
D. Increased excretion of glucose in the urine

• ✅ Correct Answer: C. Insulin resistance
• Insulin resistance is a hallmark of type 2 diabetes, where the body’s cells become less responsive to insulin, leading to elevated blood glucose levels. Over time, this condition leads to hyperglycemia as the pancreas can no longer produce enough insulin to overcome the resistance.

6. Which of the following enzymes is most commonly used to assess liver function?

A. Alkaline phosphatase (ALP)
B. Alanine aminotransferase (ALT)
C. Aspartate aminotransferase (AST)
D. Lactate dehydrogenase (LDH)

• ✅ Correct Answer: B. Alanine aminotransferase (ALT)
• ALT (also known as SGPT) is the enzyme most specific for liver injury. It is found in high concentrations in liver cells, and its elevation in the blood is a strong indicator of liver cell damage. AST is also used, but it is less liver-specific because it can be found in other tissues like the heart and muscles.

7. Which of the following is the most accurate test for assessing long-term blood glucose control in patients with diabetes?

A. Fasting blood glucose
B. Hemoglobin A1c (HbA1c)
C. Oral glucose tolerance test (OGTT)
D. Postprandial blood glucose

• ✅ Correct Answer: B. Hemoglobin A1c (HbA1c)
• HbA1c measures the average blood glucose levels over the past 2–3 months by assessing the percentage of glucose bound to hemoglobin. It is the most reliable test for long-term glucose control in diabetic patients, unlike fasting glucose or OGTT, which reflect short-term changes in blood sugar levels.

8. Which of the following is a characteristic of nephrotic syndrome?

A. Hypoalbuminemia and hyperlipidemia
B. Hypercalcemia and hypokalemia
C. Hyperglycemia and polyuria
D. Hypertension and polycythemia

• ✅ Correct Answer: A. Hypoalbuminemia and hyperlipidemia
• Nephrotic syndrome is characterized by significant proteinuria (excessive protein in urine), leading to hypoalbuminemia (low serum albumin levels). The loss of protein in the urine triggers the liver to increase production of lipoproteins, resulting in hyperlipidemia (elevated blood lipid levels). This condition often leads to edema, particularly around the eyes and ankles.

9. In which of the following conditions would you expect an elevated anion gap metabolic acidosis?

A. Diarrhea
B. Renal failure
C. Lactic acidosis
D. Hypoventilation

• ✅ Correct Answer: C. Lactic acidosis
• An elevated anion gap is typically seen in conditions where there is an accumulation of unmeasured acids in the blood, such as lactic acidosis. Lactic acid accumulates when cells undergo anaerobic metabolism, often due to severe hypoxia or sepsis. Other causes of elevated anion gap metabolic acidosis include diabetic ketoacidosis and renal failure, but lactic acidosis is particularly notable for causing this.

10. Which of the following is the most sensitive indicator of acute myocardial infarction (MI)?

A. Creatine kinase (CK-MB)
B. Troponin I
C. Myoglobin
D. Lactate dehydrogenase (LDH)

• ✅ Correct Answer: B. Troponin I
• Troponin I is the most sensitive and specific biomarker for acute myocardial infarction (MI). It is a protein released when cardiac muscle is damaged, and its levels remain elevated for several days following an MI, making it an excellent marker for early detection and long-term assessment of heart injury. CK-MB and myoglobin can also be elevated in MI, but they are less specific.

11. Which of the following laboratory findings is most characteristic of hyperaldosteronism?

A. Hyperkalemia and hyponatremia
B. Hypokalemia and hypernatremia
C. Hyperkalemia and hypercalcemia
D. Hypokalemia and hypernatremia

• ✅ Correct Answer: D. Hypokalemia and hypernatremia
• In hyperaldosteronism (also known as Conn’s syndrome), there is excessive secretion of aldosterone, which leads to sodium retention (resulting in hypernatremia) and potassium excretion (leading to hypokalemia). This can cause hypertension due to fluid retention as well. The condition often presents with these key laboratory findings, along with alkalosis.

12. Which of the following lipoproteins is responsible for transporting cholesterol from the tissues back to the liver?

A. LDL
B. VLDL
C. HDL
D. Chylomicrons

• ✅ Correct Answer: C. HDL
• HDL (High-Density Lipoprotein) is often referred to as “good cholesterol” because it transports excess cholesterol from peripheral tissues back to the liver for excretion or recycling. This process is known as reverse cholesterol transport, and higher levels of HDL are associated with a lower risk of cardiovascular disease.

13. Which of the following hormones primarily regulates calcium levels in the blood?

A. Calcitonin
B. Parathyroid hormone (PTH)
C. Aldosterone
D. Cortisol

• ✅ Correct Answer: B. Parathyroid hormone (PTH)
• Parathyroid hormone (PTH) is the main regulator of blood calcium levels. It increases calcium concentration by stimulating bone resorption, increasing renal calcium reabsorption, and enhancing intestinal calcium absorption through its role in activating vitamin D. Calcitonin has the opposite effect, lowering blood calcium levels, but its influence is less significant in adults.

14. Which analyte is most commonly used to assess renal glomerular function?

A. Uric acid
B. Creatinine
C. BUN (Blood Urea Nitrogen)
D. Cystatin C

• ✅ Correct Answer: B. Creatinine
• Creatinine is a waste product from muscle metabolism that is freely filtered by the glomeruli and not reabsorbed. It’s the most commonly used analyte to assess glomerular filtration rate (GFR) and overall kidney function. While BUN is also used, it is affected by factors like diet and hydration. Cystatin C is a newer, more sensitive marker but is not as widely used as creatinine in standard labs.

15. Which of the following is a cause of respiratory alkalosis?

A. Chronic obstructive pulmonary disease (COPD)
B. Hypoventilation
C. Anxiety-induced hyperventilation
D. Renal failure

• ✅ Correct Answer: C. Anxiety-induced hyperventilation
• Respiratory alkalosis occurs when there is excessive loss of CO₂ due to hyperventilation, which leads to an increase in blood pH. Anxiety is a common trigger, as it causes rapid, deep breathing. In contrast, hypoventilation and COPD typically cause respiratory acidosis due to CO₂ retention.

16. In electrophoresis of serum proteins, which band corresponds to immunoglobulins?

A. Albumin band
B. Alpha-1 region
C. Beta region
D. Gamma region

• ✅ Correct Answer: D. Gamma region
• In serum protein electrophoresis (SPEP), proteins are separated based on their charge and size. Immunoglobulins (antibodies) primarily migrate to the gamma region, the slowest migrating fraction toward the cathode. A broad or sharp spike in this region often indicates a polyclonal or monoclonal gammopathy, respectively, such as in multiple myeloma.

17. Which of the following analytes is most affected by hemolysis of a blood sample?

A. Glucose
B. Sodium
C. Potassium
D. Cholesterol

• ✅ Correct Answer: C. Potassium
• Potassium is primarily an intracellular cation, meaning it’s found in high concentrations inside red blood cells. When hemolysis occurs (rupture of red blood cells), potassium is released into the serum or plasma, leading to falsely elevated potassium levels (pseudohyperkalemia). This can significantly alter lab results and clinical interpretation.

18. Which test is most appropriate to assess iron storage levels in the body?

A. Serum iron
B. Total iron-binding capacity (TIBC)
C. Transferrin saturation
D. Ferritin

• ✅ Correct Answer: D. Ferritin
• Ferritin is a protein that stores iron in the body and releases it in a controlled fashion. It is the most reliable indicator of total body iron stores. Low ferritin levels indicate iron deficiency, even before anemia develops. While serum iron and TIBC can be affected by many factors, ferritin provides a clearer picture of iron status, especially in chronic diseases.

19. Which of the following enzymes is most specific for diagnosing acute pancreatitis?

A. Amylase
B. AST
C. Lipase
D. LDH

• ✅ Correct Answer: C. Lipase
• Lipase is the most specific and sensitive enzyme for diagnosing acute pancreatitis. It remains elevated longer than amylase and is more specific to pancreatic tissue. While amylase also rises in pancreatitis, it can be elevated in other conditions like salivary gland disease or intestinal obstruction, making lipase the preferred marker.

20. Which electrolyte is the major cation in extracellular fluid?

A. Potassium
B. Calcium
C. Sodium
D. Magnesium

• ✅ Correct Answer: C. Sodium
• Sodium is the primary cation in the extracellular fluid (ECF) and plays a crucial role in maintaining fluid balance, nerve function, and muscle contractions. It helps regulate blood pressure and blood volume. Potassium, in contrast, is the major cation inside cells (intracellular fluid).

21. Which of the following tests is used to assess renal function?

A. Blood glucose
B. Serum creatinine
C. Serum calcium
D. Serum albumin

• ✅ Correct Answer: B. Serum creatinine
• Serum creatinine is a key marker used to assess renal function. It is a byproduct of muscle metabolism that is filtered out by the kidneys. Elevated creatinine levels suggest decreased kidney function, as the kidneys are unable to effectively excrete creatinine. While other tests like blood glucose and albumin provide valuable information, creatinine is a direct measure of kidney performance.

22. Which of the following is a common cause of metabolic acidosis?

A. Vomiting
B. Diabetic ketoacidosis
C. Hyperventilation
D. Hyperaldosteronism

• ✅ Correct Answer: B. Diabetic ketoacidosis
• Diabetic ketoacidosis (DKA) is a serious complication of diabetes, especially in type 1, where a lack of insulin causes the body to break down fat into ketones, leading to metabolic acidosis. The accumulation of ketones in the blood lowers the pH, causing acidosis. This is in contrast to vomiting, which can lead to metabolic alkalosis, and hyperventilation, which can cause respiratory alkalosis.

23. Which of the following is a characteristic finding in multiple myeloma?

A. Decreased calcium levels
B. Increased red blood cell count
C. Increased protein in urine (Bence Jones proteins)
D. Decreased white blood cell count

• ✅ Correct Answer: C. Increased protein in urine (Bence Jones proteins)
• Multiple myeloma is a cancer of plasma cells that often results in increased protein levels in the urine, specifically Bence Jones proteins, which are free light chains of immunoglobulins. This is a hallmark finding in multiple myeloma, along with elevated serum protein levels. Other features of multiple myeloma include bone lesions, anemia, and renal impairment.

24. Which of the following would most likely result in a decreased serum calcium level?

A. Hyperparathyroidism
B. Vitamin D deficiency
C. Acromegaly
D. Osteoporosis

• ✅ Correct Answer: B. Vitamin D deficiency
• Vitamin D plays a crucial role in calcium absorption from the gastrointestinal tract. A deficiency in vitamin D can lead to decreased calcium absorption, causing hypocalcemia (low blood calcium levels). Hyperparathyroidism, on the other hand, typically causes hypercalcemia due to increased secretion of parathyroid hormone (PTH), which increases calcium levels in the blood.

25. Which of the following is the most accurate test for assessing the function of the adrenal cortex?

A. Serum cortisol
B. Plasma renin activity
C. ACTH stimulation test
D. 24-hour urinary aldosterone

• ✅ Correct Answer: C. ACTH stimulation test
• The ACTH (adrenocorticotropic hormone) stimulation test is the most accurate method to assess the function of the adrenal cortex, specifically its ability to produce cortisol in response to ACTH. In this test, synthetic ACTH is administered to stimulate the adrenal glands, and cortisol levels are measured to evaluate adrenal function. Serum cortisol alone is not as reliable because it can fluctuate throughout the day, and 24-hour urinary aldosterone is used to assess aldosterone production rather than overall adrenal function.