2026 SC Exam Prep: Specialist in Chemistry
Practice Questions, Answer Rationales,
Clinical Chemistry, Instrumentation, Quality
Assurance, Laboratory Testing &
Troubleshooting Study Guide
Domain 1: General Chemistry – Carbohydrates, Lipids, and Heme
Derivatives (Questions 1–24)
Question 1. Which method is considered the reference (definitive) method for
serum glucose measurement?
A) Glucose oxidase-peroxidase
B) Hexokinase/glucose-6-phosphate dehydrogenase
C) Ortho-toluidine condensation
D) Reducing copper (Folin-Wu)
Rationale: The hexokinase/G6PDH coupled enzymatic method is considered the
reference method for serum glucose because it is highly specific for glucose, has
minimal interference from ascorbate or uric acid, and is traceable to NIST SRM
965.
Question 2. According to ADA criteria, which fasting plasma glucose value
confirms a diagnosis of diabetes mellitus on repeat testing?
A) ≥100 mg/dL
B) ≥110 mg/dL
C) ≥126 mg/dL
D) ≥200 mg/dL
Rationale: The ADA defines diabetes by a fasting plasma glucose ≥126 mg/dL
(7.0 mmol/L) on two separate occasions, an A1c ≥6.5%, a 2-hour OGTT ≥200
mg/dL, or a random glucose ≥200 mg/dL with classic symptoms.
,Question 3. An A1c of 7.0% corresponds approximately to which estimated
average glucose (eAG)?
A) 126 mg/dL
B) 154 mg/dL
C) 183 mg/dL
D) 212 mg/dL
Rationale: Using the ADAG study formula eAG (mg/dL) = 28.7 × A1c − 46.7, an
A1c of 7.0% equals approximately 154 mg/dL. Each 1% rise in A1c reflects
roughly a 28–29 mg/dL rise in average glucose.
Question 4. Which condition would falsely lower an HbA1c result?
A) Iron deficiency anemia
B) Splenectomy
C) Hemolytic anemia
D) Aplastic anemia
Rationale: Hemolytic anemia shortens RBC lifespan, decreasing time available for
glycation and falsely lowering A1c. Other conditions that shorten RBC survival
(recent transfusion, blood loss, hemoglobinopathies SS/CC, pregnancy) similarly
lower A1c.
Question 5. A patient on an SGLT2 inhibitor presents with euglycemic
ketoacidosis. Which finding is most characteristic?
A) Glucose >500 mg/dL with positive ketones
B) Glucose <250 mg/dL with elevated beta-hydroxybutyrate
C) Negative urine glucose with elevated lactate
D) Hypoglycemia with negative ketones
Rationale: SGLT2 inhibitor-associated euglycemic diabetic ketoacidosis presents
with glucose levels typically <250 mg/dL, elevated beta-hydroxybutyrate, and
metabolic acidosis despite relatively normal glucose levels.
,Question 6. Which lipoprotein is associated with the highest risk of atherosclerosis
when elevated?
A) HDL
B) LDL
C) Chylomicrons
D) VLDL
Rationale: Elevated LDL cholesterol is the primary target for atherosclerotic
cardiovascular disease risk reduction. LDL is directly involved in plaque formation
and is the primary target of lipid-lowering therapy.
Question 7. A patient has a triglyceride level of 650 mg/dL. What is the most
important immediate concern?
A) Atherosclerosis
B) Pancreatitis
C) Fatty liver
D) Xanthomas
Rationale: Severe hypertriglyceridemia (>500 mg/dL) significantly increases the
risk of acute pancreatitis. Immediate management focuses on dietary fat restriction
and triglyceride-lowering therapy.
Question 8. Which apolipoprotein is the primary structural protein of HDL?
A) Apo B-100
B) Apo A-I
C) Apo C-II
D) Apo E
Rationale: Apo A-I is the primary structural apolipoprotein of HDL and activates
lecithin-cholesterol acyltransferase (LCAT), which is essential for reverse
cholesterol transport.
Question 9. In a patient with hemolytic jaundice, which laboratory pattern is
expected?
, A) Elevated indirect bilirubin, elevated LDH, decreased haptoglobin
B) Elevated direct bilirubin, elevated ALP, elevated GGT
C) Elevated direct and indirect bilirubin with normal LDH
D) Decreased indirect bilirubin with elevated haptoglobin
Rationale: Hemolytic jaundice is characterized by elevated indirect
(unconjugated) bilirubin, elevated LDH (released from lysed RBCs), decreased
haptoglobin (consumed by free hemoglobin), and reticulocytosis.
Question 10. Which porphyria is associated with photosensitivity and blistering
skin lesions?
A) Acute intermittent porphyria
B) Porphyria cutanea tarda
C) Lead poisoning
D) Erythropoietic protoporphyria
Rationale: Porphyria cutanea tarda (PCT) is the most common porphyria and
presents with photosensitivity, blistering skin lesions, and liver dysfunction due to
deficiency of uroporphyrinogen decarboxylase.
Question 11. Which hemoglobin derivative is measured in HbA1c testing?
A) Hemoglobin A1c (glycated hemoglobin)
B) Carboxyhemoglobin
C) Methemoglobin
D) Sulfhemoglobin
Rationale: HbA1c measures the fraction of hemoglobin that has been irreversibly
glycated at the N-terminal valine of the beta chain, reflecting average glucose over
the preceding 2–3 months.
Question 12. Which of the following is a cause of falsely elevated HbA1c?
A) Hemolytic anemia
B) Iron deficiency anemia
Practice Questions, Answer Rationales,
Clinical Chemistry, Instrumentation, Quality
Assurance, Laboratory Testing &
Troubleshooting Study Guide
Domain 1: General Chemistry – Carbohydrates, Lipids, and Heme
Derivatives (Questions 1–24)
Question 1. Which method is considered the reference (definitive) method for
serum glucose measurement?
A) Glucose oxidase-peroxidase
B) Hexokinase/glucose-6-phosphate dehydrogenase
C) Ortho-toluidine condensation
D) Reducing copper (Folin-Wu)
Rationale: The hexokinase/G6PDH coupled enzymatic method is considered the
reference method for serum glucose because it is highly specific for glucose, has
minimal interference from ascorbate or uric acid, and is traceable to NIST SRM
965.
Question 2. According to ADA criteria, which fasting plasma glucose value
confirms a diagnosis of diabetes mellitus on repeat testing?
A) ≥100 mg/dL
B) ≥110 mg/dL
C) ≥126 mg/dL
D) ≥200 mg/dL
Rationale: The ADA defines diabetes by a fasting plasma glucose ≥126 mg/dL
(7.0 mmol/L) on two separate occasions, an A1c ≥6.5%, a 2-hour OGTT ≥200
mg/dL, or a random glucose ≥200 mg/dL with classic symptoms.
,Question 3. An A1c of 7.0% corresponds approximately to which estimated
average glucose (eAG)?
A) 126 mg/dL
B) 154 mg/dL
C) 183 mg/dL
D) 212 mg/dL
Rationale: Using the ADAG study formula eAG (mg/dL) = 28.7 × A1c − 46.7, an
A1c of 7.0% equals approximately 154 mg/dL. Each 1% rise in A1c reflects
roughly a 28–29 mg/dL rise in average glucose.
Question 4. Which condition would falsely lower an HbA1c result?
A) Iron deficiency anemia
B) Splenectomy
C) Hemolytic anemia
D) Aplastic anemia
Rationale: Hemolytic anemia shortens RBC lifespan, decreasing time available for
glycation and falsely lowering A1c. Other conditions that shorten RBC survival
(recent transfusion, blood loss, hemoglobinopathies SS/CC, pregnancy) similarly
lower A1c.
Question 5. A patient on an SGLT2 inhibitor presents with euglycemic
ketoacidosis. Which finding is most characteristic?
A) Glucose >500 mg/dL with positive ketones
B) Glucose <250 mg/dL with elevated beta-hydroxybutyrate
C) Negative urine glucose with elevated lactate
D) Hypoglycemia with negative ketones
Rationale: SGLT2 inhibitor-associated euglycemic diabetic ketoacidosis presents
with glucose levels typically <250 mg/dL, elevated beta-hydroxybutyrate, and
metabolic acidosis despite relatively normal glucose levels.
,Question 6. Which lipoprotein is associated with the highest risk of atherosclerosis
when elevated?
A) HDL
B) LDL
C) Chylomicrons
D) VLDL
Rationale: Elevated LDL cholesterol is the primary target for atherosclerotic
cardiovascular disease risk reduction. LDL is directly involved in plaque formation
and is the primary target of lipid-lowering therapy.
Question 7. A patient has a triglyceride level of 650 mg/dL. What is the most
important immediate concern?
A) Atherosclerosis
B) Pancreatitis
C) Fatty liver
D) Xanthomas
Rationale: Severe hypertriglyceridemia (>500 mg/dL) significantly increases the
risk of acute pancreatitis. Immediate management focuses on dietary fat restriction
and triglyceride-lowering therapy.
Question 8. Which apolipoprotein is the primary structural protein of HDL?
A) Apo B-100
B) Apo A-I
C) Apo C-II
D) Apo E
Rationale: Apo A-I is the primary structural apolipoprotein of HDL and activates
lecithin-cholesterol acyltransferase (LCAT), which is essential for reverse
cholesterol transport.
Question 9. In a patient with hemolytic jaundice, which laboratory pattern is
expected?
, A) Elevated indirect bilirubin, elevated LDH, decreased haptoglobin
B) Elevated direct bilirubin, elevated ALP, elevated GGT
C) Elevated direct and indirect bilirubin with normal LDH
D) Decreased indirect bilirubin with elevated haptoglobin
Rationale: Hemolytic jaundice is characterized by elevated indirect
(unconjugated) bilirubin, elevated LDH (released from lysed RBCs), decreased
haptoglobin (consumed by free hemoglobin), and reticulocytosis.
Question 10. Which porphyria is associated with photosensitivity and blistering
skin lesions?
A) Acute intermittent porphyria
B) Porphyria cutanea tarda
C) Lead poisoning
D) Erythropoietic protoporphyria
Rationale: Porphyria cutanea tarda (PCT) is the most common porphyria and
presents with photosensitivity, blistering skin lesions, and liver dysfunction due to
deficiency of uroporphyrinogen decarboxylase.
Question 11. Which hemoglobin derivative is measured in HbA1c testing?
A) Hemoglobin A1c (glycated hemoglobin)
B) Carboxyhemoglobin
C) Methemoglobin
D) Sulfhemoglobin
Rationale: HbA1c measures the fraction of hemoglobin that has been irreversibly
glycated at the N-terminal valine of the beta chain, reflecting average glucose over
the preceding 2–3 months.
Question 12. Which of the following is a cause of falsely elevated HbA1c?
A) Hemolytic anemia
B) Iron deficiency anemia
