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WorksheetsCHEM exam review part 2
Total questions: 91
Worksheet time: 46mins
A patient’s SPE shows a narrow, sharp spike in the gamma region. Which condition is most likely?
Cirrhosis
Multiple Myeloma
Acute inflammation
α₁-Antitrypsin deficiency
Which serum protein is decreased in α₁-antitrypsin deficiency and migrates in the α₁ region?
Albumin
Haptoglobin
α₁-Antitrypsin
Immunoglobulin A
Which method identifies the specific type of monoclonal immunoglobulin?
Biuret method
Radial immunodiffusion
Immunofixation electrophoresis
Mass spectrometry
In nephrotic syndrome, which of the following patterns is typically seen on SPE?
Sharp M-spike
Beta-gamma bridging
Decreased albumin, increased α₂ and β
Elevated γ region
What would a low A:G ratio typically indicate?
Dehydration
Liver failure or chronic inflammation
Iron deficiency
Immunodeficiency
Which electrolyte is the major intracellular cation?
Sodium
Potassium
Calcium
Chloride
Which hormone directly increases sodium reabsorption in the kidneys?
ADH
Renin
Aldosterone
Cortisol
A serum chloride level of 93 mmol/L would be considered:
Hyperchloremia
Hypochloremia
Normal
Artifact
A potassium result of 6.2 mmol/L might be falsely elevated due to:
Vomiting
Dehydration
Hemolysis
Fever
Which of the following values indicates hyponatremia?
142 mmol/L
135 mmol/L
130 mmol/L
150 mmol/L
Which method is most commonly used on automated chemistry analyzers to measure chloride?
Flame photometry
Ion-selective electrode
Turbidimetry
Nephelometry
Which of the following causes a loss of bicarbonate, contributing to metabolic acidosis?
Vomiting
Diarrhea
Hyperventilation
Dehydration
Which lab pattern is consistent with metabolic alkalosis?
↓ pH, ↓ HCO₃⁻
↑ pH, ↑ HCO₃⁻
↓ pH, ↑ CO₂
↑ pH, ↓ CO₂
What electrolyte is most closely associated with neuromuscular function and cardiac rhythm?
Sodium
Chloride
Bicarbonate
Potassium
A sodium of 148 mmol/L, in the absence of disease, could be caused by:
Water overload
SIADH
Dehydration
Renal failure
Which of the following electrolytes is the major intracellular cation responsible for nerve conductivity and muscle contractility?
Sodium
Potassium
Chloride
Bicarbonate
What is the main physiological role of sodium (Na⁺) in the body?
Acid-base buffering
Maintains intracellular volume
Maintains water distribution and osmotic pressure
Facilitates glucose transport
Which anion is the second most abundant in extracellular fluid and plays a major role in acid-base balance?
Chloride
Phosphate
Sulfate
Bicarbonate
Which method is used to measure potassium levels in clinical laboratories?
Flame photometry
Ion-selective electrode with valinomycin
Turbidimetric assay
Atomic absorption spectrometry
Sodium is measured by ion-selective electrodes. What compound provides specificity for sodium in these electrodes?
Valinomycin
Glass membrane
Silicon dioxide
Polyacrylamide
Which method is commonly used for bicarbonate measurement on automated analyzers?
Nephelometry
Enzymatic assay
Turbidimetry
Spectrophotometry
What preanalytical error can falsely elevate measured potassium levels?
Lipemia
Exposure to air
Hemolysis of blood sample
Protein contamination
A blood gas analyzer's sodium ISE is exposed to air. What is the likely result?
No effect
Decreased potassium
Falsely low sodium
Electrode malfunction due to build-up
What is the adult reference range for serum sodium?
130–140 mmol/L
125–135 mmol/L
135–145 mmol/L
140–150 mmol/L
Which of the following potassium values is considered a critical high value for adults?
4.5 mmol/L
5.6 mmol/L
6.5 mmol/L
7.8 mmol/L
What is the normal reference range for serum chloride in mmol/L?
90–100
96–106
105–115
100–110
A patient with severe diarrhea is likely to show:
Hypernatremia and hypokalemia
Hyponatremia and hyperkalemia
Hypochloremia and metabolic alkalosis
Hyponatremia and metabolic acidosis
Which condition is associated with increased bicarbonate levels?
Metabolic acidosis
Respiratory alkalosis
Severe vomiting
Chronic diarrhea
Which of the following can cause hyperkalemia?
Loop diuretic therapy
Insulin overdose
Renal failure
Prolonged vomiting
Which hormone promotes sodium reabsorption and potassium excretion in the kidneys?
Renin
Angiotensin I
Aldosterone
ADH
The release of renin leads to the production of which potent vasoconstrictor?
Aldosterone
ADH
Angiotensin II
Cortisol
What is the main effect of antidiuretic hormone (ADH) on water balance?
Promotes sodium excretion
Inhibits aldosterone
Promotes water reabsorption in the kidneys
Stimulates renin secretion
A magnesium level of 0.58 mmol/L is best interpreted as:
Normal
Increased
Decreased – Hypomagnesemia
Increased – Hypermagnesemia
A serum calcium level of 11.5 mg/dL indicates:
Hypocalcemia
Hypercalcemia
Normal calcium
Calcium deficiency
A phosphate result of 5.2 mg/dL would be classified as:
Hypophosphatemia
Hyperphosphatemia
Normal
Phosphorus wasting
Which of the following electrolytes is commonly falsely elevated in a hemolyzed sample?
Sodium
Calcium
Potassium
Chloride
Which of the following electrolytes is commonly falsely elevated in a hemolyzed sample?
Sodium
Calcium
Potassium
Chloride
Which two other elements may also appear falsely increased due to hemolysis? (Select two)
Magnesium
Iron
Phosphate
Bicarbonate
What is the major intracellular anion?
Chloride
Bicarbonate
Phosphate
Sulfate
What is the primary acid-base buffer system in urine?
Bicarbonate buffer
Ammonia buffer
Phosphate buffer
Protein buffer
What does it mean if an analyte exhibits diurnal variation?
It changes with temperature
It fluctuates based on food intake
Its levels vary throughout the day
It is affected by circadian rhythm only at night
Which anion exhibits diurnal variation?
Bicarbonate
Phosphate
Sulfate
Chloride
What effect does parathyroid hormone (PTH) have on calcium levels?
Decreases serum calcium
Promotes calcium excretion
Increases serum calcium by acting on bone and kidneys
Inhibits vitamin D production
What is the primary action of vitamin D on calcium levels?
Promotes calcium loss in stool
Inhibits PTH
Enhances calcium absorption from the gut
Decreases calcium reabsorption in kidneys
What is the main action of calcitonin?
Raises serum calcium
Stimulates osteoclast activity
Increases calcium absorption in intestines
Lowers serum calcium by promoting bone deposition
Which colorimetric reagent is used for measuring magnesium on automated instruments?
Arsenazo III
Xylidyl Blue
Ammonium Molybdate
Cresolphthalein Complexone
Which reagent is used for the colorimetric measurement of calcium?
Xylidyl Blue
Arsenazo III
Ammonium Molybdate
Ion-selective membrane
The most common reagent for phosphate measurement is:
Alkaline picrate
Arsenazo III
Ammonium Molybdate
Tetrabromophenol Blue
Which of the following is NOT a function of calcium (Ca²⁺) in the body?
Blood coagulation
Neuromuscular excitability
Insulin secretion
Bone mineralization
Magnesium (Mg²⁺) is essential for which of the following functions?
Antibody synthesis
Platelet aggregation
ATP metabolism and PTH secretion
Hemoglobin oxygen binding
Which of the following is a major role of phosphate (PO₄³⁻)?
Stabilizing DNA secondary structure
Bone health and energy storage
Iron absorption
Cellular oxygen transport
Which method is commonly used to measure total calcium in serum?
Atomic absorption
Colorimetric (e.g., OCPC or CPC methods)
Ion-selective electrode only
Immunoassay
Which colorimetric reagent is used in magnesium assays?
Arsenazo III
Xylidyl Blue
Ammonium molybdate
Cresolphthalein
Phosphate is measured by forming which colorimetric complex?
Calcium-oxalate
Magnesium-calcein
Ammonium phosphomolybdate
Xylenol orange
What factor can falsely lower ionized calcium measurements?
High vitamin D
Heparin contamination in collection syringe
High protein diet
Hyperphosphatemia
What issue can affect both calcium and magnesium colorimetric assays?
Alkalosis
Hyperglycemia
Ascorbic acid interference
Light exposure
What is the reference interval for total calcium in adults?
7.5–9.5 mg/dL
8.0–10.0 mg/dL
9.0–10.5 mg/dL
10.5–12.5 mg/dL
What is the critical value for low serum magnesium?
<1.2 mg/dL
<1.0 mg/dL
<1.5 mg/dL
<1.8 mg/dL
Which of the following is the normal range for inorganic phosphate?
1.5–3.0 mg/dL
2.5–4.5 mg/dL
3.5–5.5 mg/dL
4.5–6.5 mg/dL
Which condition is most likely to cause hypercalcemia?
Vitamin D deficiency
Chronic renal failure
Primary hyperparathyroidism
Hypoparathyroidism
Which condition is associated with hypomagnesemia?
Renal failure
Excessive Mg supplements
Alcoholism and GI losses
Hyperthyroidism
What can cause hyperphosphatemia?
Vitamin D deficiency
Tumor lysis syndrome
Hyperparathyroidism
Malnutrition
What is the role of calcitonin in calcium regulation?
Raises blood calcium by resorbing bone
Promotes calcium excretion and reduces resorption
Inhibits vitamin D production
Stimulates intestinal calcium absorption
How does parathyroid hormone (PTH) raise calcium levels?
Inhibits bone resorption and decreases renal reabsorption
Stimulates bone resorption and renal calcium retention
Promotes intestinal calcium excretion
Suppresses vitamin D synthesis
What is the role of vitamin D in calcium regulation?
Promotes calcium excretion
Decreases calcium absorption in the intestines
Increases calcium absorption and bone mineralization
Inhibits bone formation
How does PTH affect phosphate levels?
Increases reabsorption in kidneys
Lowers phosphate by promoting renal excretion
Enhances phosphate absorption in the gut
No effect on phosphate
Which hormone increases serum phosphate by enhancing kidney reabsorption?
Calcitonin
Growth hormone
Cortisol
Insulin
A patient has high calcium, low phosphate, and elevated PTH. Which condition is most likely?
Hypoparathyroidism
Primary hyperparathyroidism
Vitamin D deficiency
Renal failure
A patient with hypocalcemia also has low magnesium. Which of the following is true?
High Mg suppresses PTH
Low Mg enhances PTH
Low Mg can suppress PTH, contributing to hypocalcemia
Mg has no effect on calcium metabolism
What is this patient’s anion gap (AG)? Use: AG = Na⁺ + K⁺ – (Cl⁻ + HCO₃⁻)
28.2
32.8
24.5
15.5
What is this patient’s anion gap (AG)? Use: AG = Na⁺ + K⁺ – (Cl⁻ + HCO₃⁻)
28.2
32.8
24.5
15.5
What is the calculated serum osmolality for this patient? Use: Osm = 1.86(Na⁺) + Glucose/18 + BUN/2.8 + 9
290 mOsm/kg
275 mOsm/kg
265 mOsm/kg
305 mOsm/kg
What is the osmolal gap? Use: Osmolal Gap = Measured – Calculated
55
65
75
85
What acid-base disturbance is indicated by the following values? HCO₃⁻: 10 mmol/L, pH: 7.30
Metabolic acidosis
Respiratory alkalosis
Metabolic alkalosis
Respiratory acidosis
Which condition is most likely causing the metabolic acidosis and elevated osmolal gap in this patient?
Diarrhea
Chronic renal failure
Ethylene glycol poisoning
Diabetic ketoacidosis
Why is the patient’s bicarbonate decreased?
Loss via kidneys due to diuretic therapy
Dilutional effect due to fluid overload
It was used to buffer excess organic acids
Reduced synthesis in liver
What is the clinical significance of the anion gap in acid-base evaluation?
It reflects water retention status
It helps detect unmeasured anions in metabolic acidosis
It identifies dehydration
It measures the total body sodium level
What is the clinical use of the osmolal gap?
Identifying viral infections
Measuring intracellular pH
Detecting unmeasured osmotically active substances (e.g., alcohols)
Calculating anion gap
Which formula correctly calculates the anion gap (AG)?
(Na⁺ + Cl⁻) – (K⁺ + HCO₃⁻)
(Na⁺ + K⁺) – (Cl⁻ + HCO₃⁻)
(Na⁺ + HCO₃⁻) – (K⁺ + Cl⁻)
(Cl⁻ + HCO₃⁻) – (Na⁺ + K⁺)
Which equation is used to calculate serum osmolality?
Na⁺ × 2 + BUN × 3 + Glucose × 2
1.86(Na⁺) + Glucose/18 + BUN/2.8 + 9
Na⁺ + Cl⁻ + HCO₃⁻ + BUN
1.86(Na⁺ + K⁺) + Glucose/2 + BUN × 2
What is the normal range for calculated serum osmolality?
250–270 mOsm/kg
280–310 mOsm/kg
275–295 mOsm/kg
260–275 mOsm/kg
Which value indicates an abnormal osmolal gap?
10
12
14
20
What triggers the kidney to retain sodium via the renin-angiotensin system?
Hypernatremia
Dehydration and low blood pressure
Hyperkalemia
High BUN
How is potassium affected in metabolic acidosis (acidemia)?
K⁺ enters cells as H⁺ exits
K⁺ exits cells as H⁺ enters
Both ions remain unchanged
K⁺ is excreted in sweat
What happens to potassium in metabolic alkalosis (alkalemia)?
Potassium is released from cells into plasma
Potassium is excreted in urine
Potassium enters cells as H⁺ exits
Potassium binds to albumin
Which of the following best describes an uncompensated acid-base disorder?
pH is normal; both bicarbonate and PCO2 are abnormal
pH is outside reference interval; either bicarbonate or PCO2 is abnormal, but not both
pH is outside reference interval; both bicarbonate and PCO2 are abnormal
pH is normal; bicarbonate and PCO2 are both abnormal
What characterizes a partially compensated acid-base disorder?
pH normal, bicarbonate and PCO2 abnormal
pH outside reference interval, bicarbonate and PCO2 abnormal
pH nearing normal, bicarbonate and PCO2 abnormal
pH outside reference interval, bicarbonate or PCO2 abnormal
In a fully compensated acid-base disorder, what is true?
pH outside reference interval, bicarbonate and PCO2 normal
pH normal, bicarbonate and PCO2 abnormal, ratio ~20:1
pH outside reference interval, only bicarbonate abnormal
pH normal, bicarbonate and PCO2 both normal
Patient #1 has pH 7.31 (low), PCO2 32 mmHg (low), HCO3- 15 mmol/L (low). What is the acid-base status?
Metabolic acidosis, uncompensated
Metabolic acidosis, partially compensated
Respiratory acidosis, fully compensated
Metabolic alkalosis, uncompensated
Patient #2 has pH 7.58 (high), PCO2 42 mmHg (normal), HCO3- 38 mmol/L (high). What is the acid-base status?
Metabolic alkalosis, uncompensated
Respiratory alkalosis, fully compensated
Metabolic acidosis, partially compensated
Respiratory acidosis, uncompensated
Patient #3 has pH 7.37 (normal), PCO2 60 mmHg (high), HCO3- 34 mmol/L (high). What is the acid-base status?
Respiratory acidosis, uncompensated
Respiratory acidosis, partially compensated
Respiratory acidosis, fully compensated
Metabolic alkalosis, uncompensated
