Clinical chemistry Practice Exam
Test Your Knowledge with These Key Questions
1. Electrolytes are essential for maintaining fluid balance and proper nerve function in the body. Among these, which electrolyte serves as the primary cation found outside the cells?
A. Potassium
B. Sodium
C. Calcium
D. Magnesium
2. Inflammation of the pancreas causes the release of specific enzymes into the bloodstream, which help in diagnosis. What enzyme is most commonly elevated in pancreatitis?
A. ALT
B. AST
C. Amylase
D. LDH
3. Maintaining normal potassium levels is essential for muscle and nerve function. What is the normal reference range for serum potassium in adults?
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
4. In cases of liver or biliary tract disorders, specific substances can accumulate in the bloodstream due to impaired bile flow. 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
5. In diabetes mellitus, certain physiological changes lead to elevated blood glucose levels. What is the 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
6. Specific biochemical markers are routinely used to assess function when evaluating liver health. Which of the following is most commonly used to assess liver function?
A. Alkaline phosphatase (ALP)
B. Alanine aminotransferase (ALT)
C. Aspartate aminotransferase (AST)
D. Lactate dehydrogenase (LDH)
7. Monitoring long-term glycemic control is crucial for preventing complications when managing diabetes. What 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
8. Recognizing hallmark laboratory findings is essential in evaluating kidney disorders. 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
9. In the context of acid-base imbalances, some clinical conditions are known to cause an elevated anion gap. Which of the following conditions would you expect an elevated anion gap metabolic acidosis?
A. Diarrhea
B. Renal failure
C. Lactic acidosis
D. Hypoventilation
10. When evaluating a patient for a possible heart attack, certain biomarkers are more sensitive than others. It is the most sensitive indicator of acute myocardial infarction (MI).
A. Creatine kinase (CK-MB)
B. Troponin I
C. Myoglobin
D. Lactate dehydrogenase (LDH)
11. Understanding endocrine imbalances helps in identifying hormone-related disorders. Which of the following laboratory findings is the most characteristic of hyperaldosteronism?
A. Hyperkalemia and hyponatremia
B. Hypokalemia and hypernatremia
C. Hyperkalemia and hypercalcemia
D. Hypokalemia and hypernatremia
12. In cardiovascular risk assessment, it is essential to understand the lipid transport mechanism. 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
13. Calcium homeostasis is tightly regulated to support vital physiological processes such as muscle contraction and nerve signalling. The hormones that primarily regulate calcium levels in the blood include which of the following?
A. Calcitonin
B. Parathyroid hormone (PTH)
C. Aldosterone
D. Cortisol
14. When evaluating kidney health, specific biomarkers are essential in determining how well the glomeruli are filtering the blood. Which analyte is most commonly used to assess renal glomerular function?
A. Uric acid
B. Creatinine
C. BUN (Blood Urea Nitrogen)
D. Cystatin C
15. Disturbances in acid-base balance can provide important clues to underlying respiratory or metabolic conditions. 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
16. Serum protein electrophoresis separates proteins based on their size and charge, providing important diagnostic clues. Which band corresponds to immunoglobulins?
A. Albumin band
B. Alpha-1 region
C. Beta region
D. Gamma region
17. During blood sample collection and handling, certain analytes can be significantly altered by cell damage. Which of the following analytes is most affected by hemolysis of a blood sample?
A. Glucose
B. Sodium
C. Potassium
D. Cholesterol
18. Iron metabolism is crucial for red blood cell production and overall oxygen transport in the body. What is the most appropriate test to assess iron storage levels in the body?
A. Serum iron
B. Total iron-binding capacity (TIBC)
C. Transferrin saturation
D. Ferritin
19. When evaluating a patient for acute pancreatitis, it is important to identify the most specific enzyme indicative of pancreatic inflammation.
Which enzyme is the most specific for diagnosing acute pancreatitis?
A. Amylase
B. AST
C. Lipase
D. LDH
20. Electrolyte balance is vital for nerve impulse transmission and muscle function. Which electrolyte is the major cation in extracellular fluid?
A. Potassium
B. Calcium
C. Sodium
D. Magnesium
21. Kidney function assessment plays a vital role in diagnosing renal disorders. Which of the following tests is used to assess renal function?
A. Blood glucose
B. Serum creatinine
C. Serum calcium
D. Serum albumin
22. Understanding the underlying causes of acid-base imbalances is crucial in clinical diagnosis. What is the common cause of metabolic acidosis?
A. Vomiting
B. Diabetic ketoacidosis
C. Hyperventilation
D. Hyperaldosteronism
23. In evaluating plasma cell disorders, recognizing hallmark laboratory findings is essential. 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
24. Calcium homeostasis is tightly regulated by hormonal and physiological mechanisms. Which of the following would most likely result in a decreased serum calcium level?
A. Hyperparathyroidism
B. Vitamin D deficiency
C. Acromegaly
D. Osteoporosis
25. Evaluating adrenal cortex function is essential in diagnosing endocrine disorders. The most accurate test for assessing the function of the adrenal cortex is:
A. Serum cortisol
B. Plasma renin activity
C. ACTH stimulation test
D. 24-hour urinary aldosterone
26. What is the correct formula relating absorbance (A) and percent transmittance (%T) in spectrophotometry?
A. A = log %T
B. A = 2 – log %T
C. A = %T ÷ 100
D. A = 1/%T
27. A solution has 1% transmittance. What is the absorbance?
A. 1.0
B. 2.0
C. 0.1
D. 100
28. Which glucose testing scenario is appropriate for point-of-care whole-blood methods?
A. Screening for type 2 diabetes
B. Diagnosis of diabetes mellitus
C. Monitoring day-to-day glucose control
D. Diagnosing hyperosmolar crisis
29. A red-colored solution will strongly absorb light in which range?
A. 600–650 nm
B. 400–500 nm
C. 700–800 nm
D. 300–350 nm
30. Which genetic alteration is most commonly linked to increased overall cancer risk?
A. EGFR mutation
B. p53 mutation
C. HER2 amplification
D. BCR–ABL fusion
31. In Beer’s law, doubling the cuvette path length while keeping concentration constant will:
A. Halve the absorbance
B. Double the absorbance
C. Not affect absorbance
D. Eliminate transmittance
32. Which metabolite is most often increased in carcinoid syndrome?
A. 5-Hydroxyindoleacetic acid (5-HIAA)
B. 3-Methoxy-4-hydroxyphenylglycol (MHPG)
C. 3-Methoxydopamine
D. Homovanillic acid (HVA)
33. Which wavelength is best for quantifying a green solution?
A. 450 nm
B. 525 nm
C. 650 nm
D. 700 nm
34. Which condition shifts the oxyhemoglobin dissociation curve to the right?
A. Alkalosis
B. Acidosis
C. Multiple transfusions
D. Increased HbC
35. Which method is the reference method for serum glucose measurement?
A. Somogyi–Nelson
B. Hexokinase
C. Glucose oxidase
D. Glucose dehydrogenase
36. A lipemic serum sample shows low sodium by indirect ISE. What is the most likely explanation?
A. Excess renal sodium loss
B. Pseudohyponatremia
C. True hyponatremia
D. Hemolysis interference
37. Which annual test is recommended for diabetic patients in addition to glucose, HbA1c, and
microalbumin?
A. Serum ketones
B. Random glucose
C. Estimated glomerular filtration rate (eGFR)
D. Urine glucose
38. Which 24-hour urine assay is the best single screening test for pheochromocytoma?
A. Total catecholamines
B. Vanillylmandelic acid (VMA)
C. Homovanillic acid (HVA)
D. Metanephrines
39. A child has elevated urinary HVA and VMA with increased neuron-specific enolase (NSE), but
normal 5-HIAA. Most likely diagnosis?
A. Carcinoid tumor
B. Pheochromocytoma
C. Neuroblastoma
D. Pancreatic carcinoma
40. A patient has total protein 5.1 g/dL and albumin 4.8 g/dL. What is the next best step?
A. Request a new specimen
B. Repeat total protein
C. Repeat all tests
D. Perform protein electrophoresis
41. Which HbA1c range defines increased risk (prediabetes)?
A. <5.0%
B. 5.0%–5.5%
C. 5.7%–6.4%
D. ≥6.5%
42. Which property of plasma catecholamines complicates interpretation compared to urinary
metabolites?
A. Stable excretion profile
B. Diurnal and pulsatile variation
C. Consistency during stress
D. Excreted unchanged in urine
43. According to ADA criteria, which HbA1c value is diagnostic for diabetes mellitus?
A. 5.7%
B. 6.5% or higher
C. 7.0% or higher
D. 5.0% or higher
44. Which screening test is recommended for colorectal cancer in adults over 50?
A. Carcinoembryonic antigen (CEA)
B. Fecal occult blood test (FOBT/FIT)
C. Alpha-fetoprotein (AFP)
D. Fecal trypsin
45. Which urinary metabolite is typically elevated in carcinoid tumors?
A. Homovanillic acid (HVA)
B. Vanillylmandelic acid (VMA)
C. 5-Hydroxyindoleacetic acid (5-HIAA)
D. Metanephrines
46. Which specimen is NOT acceptable as a primary sample for amphetamine testing?
A. Serum
B. Urine
C. Gastric fluid
D. Plasma
47. Which test best distinguishes primary from secondary Addison’s disease?
A. Serum cortisol alone
B. Plasma ACTH
C. Urine free cortisol
D. Serum aldosterone
48. Which tumor marker is most associated with hepatocellular carcinoma?
A. Alpha-fetoprotein (AFP)
B. Carcinoembryonic antigen (CEA)
C. CA 19-9
D. Prostate-specific antigen (PSA)
49. A red-colored solution will strongly absorb light in which range?
A. 600–650 nm
B. 400–500 nm
C. 700–800 nm
D. 300–350 nm
50. Which glucose testing scenario is appropriate for point-of-care whole-blood methods?
A. Screening for type 2 diabetes
B. Diagnosis of diabetes mellitus
C. Monitoring day-to-day glucose control
D. Diagnosing hyperosmolar crisis