Harr Clinical Chemistry UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Select the most appropriate adult reference range for fasting blood glucose.
A. 40-105 mg/dL (2.22-5.82 mmol/L)
B. 60-140 mg/dL (3.33-7.77 mmol/L)
C. 65-99 mg/dL (3.61-5.50 mmol/L)
D. 75-150 mg/dL (4.16-8.32 mmol/L) - CORRECT ANSWER- ✔✔C. 65-99 mg/dL (3.61-
5.50 mmol/L)
C Reference ranges vary slightly depending upon method and specimen type. Enzymatic
methods specific for glucose have an upper limit of normal no greater than 99 mg/dL. This is
the cutoff value for impaired fasting plasma glucose (prediabetes) recommended by the
American Diabetes Association. Although 65 mg/dL is considered the 2.5 percentile, a fasting
level below 50 mg/dL is often seen without associated clinical hypoglycemia, and neonates
have a lower limit of approximately 40 mg/dL owing to maternal insulin
When preparing a patient for an oral glucose tolerance test (OGTT), which of the following
conditions will lead to erroneous results?
A. The patient remains ambulatory for 3 days prior to the test
B. Carbohydrate intake is restricted to below 150 g/day for 3 days prior to test
C. No food, coffee, tea, or smoking is allowed 8 hours before and during the test
D. Administration of 75 g of glucose is given to an adult patient following a 10-12-hour fast -
CORRECT ANSWER- ✔✔B. Carbohydrate intake is restricted to below 150 g/day for 3 days
prior to test
B Standardized OGTTs require that patients receive at least 150 grams of carbohydrate per
day for 3 days prior to the test in order to stabilize the synthesis of inducible glycolytic
enzymes. The 2-hour OGTT test is no longer recommended for screening and should be
reserved for confirmation of diabetes in cases that are difficult to diagnose, such as persons
who lack symptoms and signs of fasting hyperglycemia.
,Which of the following 2-hour glucose challenge results would be classified as impaired
glucose tolerance (IGT)?
Two-hour serum glucose:
A. 130 mg/dL
B. 135 mg/dL
C. 150 mg/dL
D. 204 mg/dL - CORRECT ANSWER- ✔✔C. 150 mg/dL
C With the exception of pregnant females, impaired glucose tolerance is defined by the ADA
as a serum or plasma glucose at 2 hours following a 75-g oral glucose load of ≥140 mg/dL
and < 200 mg/dL. Persons who have a fasting plasma glucose of ≥100 but < 126 mg/dL are
classified as having impaired fasting glucose (IFG). Both IGT and IFG are risk factors for
developing diabetes later in life. Such persons are classified as having prediabetes and should
be tested annually.
Which statement regarding gestational diabetes mellitus (GDM) is correct?
A. Is diagnosed using the same oral glucose tolerance criteria as in nonpregnancy
B. Converts to diabetes mellitus after pregnancy in 60%-75% of cases
C. Presents no increased health risk to the fetus
D. Is defined as glucose intolerance originating during pregnancy - CORRECT ANSWER-
✔✔D. Is defined as glucose intolerance originating during pregnancy
D Control of GDM reduces perinatal complications such as respiratory distress syndrome,
high birth weight, and neonatal jaundice. Women at risk are usually screened between 24 and
28 weeks' gestation. The screening test can be performed nonfasting and consists of an oral
50-g glucose challenge followed by serum or plasma glucose measurement at 1 hour. A result
≥ 140 mg/dL is followed by a 2-hour or 3-hour oral glucose tolerance test to confirm
gestational diabetes. For the 3-hour test, a 100-g dose of glucose is used and at least two of
the following cutoffs must be exceeded: fasting, ≥ 95 mg/dL or higher; 1 hour, ≥ 180 mg/dL
or higher; 2 hour ≥ 155 mg/dL or higher; 3 hour, ≥ 140 mg/dL or higher. The same cutpoints
are used for the 2-hour test except that a 75-g dose is used. GDM converts to diabetes
mellitus within 10 years in 30%-40% of cases. ADA recommends testing persons with GDM
for diabetes 6-12 weeks after delivery
, Which of the following findings is characteristic of all forms of clinical hypoglycemia?
A. A fasting blood glucose value below 55 mg/dL
B. High fasting insulin levels
C. Neuroglycopenic symptoms at the time of low blood sugar
D. Decreased serum C peptide - CORRECT ANSWER- ✔✔C Clinical hypoglycemia can be
caused by insulinoma, drugs, alcoholism, and reactive hypoglycemia. Neuroglycopenic
symptoms at the time of low blood sugar
C. Reactive hypoglycemia is characterized by delayed or excessive insulin output after eating
and is very rare. Fasting insulin is normal but postprandial levels are increased. High fasting
insulin levels (usually > 6 μg/L) are seen in insulinoma, and patients with insulinoma almost
always display fasting hypoglycemia, especially when the fast is extended to 48 72 hours. C
peptide is a subunit of proinsulin that is hydrolyzed when insulin is released. In
hypoglycemia, low levels indicate an exogenous insulin source, whereas high levels indicate
overproduction of insulin.
Which statement regarding glycated (glycosylated) Hgb (G-Hgb) is true?
A. Has a sugar attached to the C-terminal end of the β chain
B. Is a highly reversible aminoglycan
C. Reflects the extent of glucose regulation in the 8- to 12-week interval prior to sampling
D. Will be abnormal within 4 days following an episode of hyperglycemia - CORRECT
ANSWER- ✔✔C. Reflects the extent of glucose regulation in the 8- to 12-week interval prior
to sampling
C G-Hgb results from the nonenzymatic attachment of a sugar such as glucose to the N-
terminal valine of the β chain. The reaction is nonreversible and is related to the time-
averaged blood glucose concentration over the life span of the RBCs. There are three G-Hgb
fractions designated A1a, A1b, and Alc. Hemoglobin A1c makes up about 80% of glycated
hemoglobin, and is used to determine the adequacy of insulin therapy. The time-averaged
blood glucose is approximated by the formula (G-Hgb × 33.3) - 86 mg/dL, and insulin
adjustments can be made to bring this level to within reference limits. Also, glycated protein
assay (called fructosamine) provides similar data for the period between 2 and 4 weeks before
sampling.
ACTUAL Exam Questions and CORRECT
Answers
Select the most appropriate adult reference range for fasting blood glucose.
A. 40-105 mg/dL (2.22-5.82 mmol/L)
B. 60-140 mg/dL (3.33-7.77 mmol/L)
C. 65-99 mg/dL (3.61-5.50 mmol/L)
D. 75-150 mg/dL (4.16-8.32 mmol/L) - CORRECT ANSWER- ✔✔C. 65-99 mg/dL (3.61-
5.50 mmol/L)
C Reference ranges vary slightly depending upon method and specimen type. Enzymatic
methods specific for glucose have an upper limit of normal no greater than 99 mg/dL. This is
the cutoff value for impaired fasting plasma glucose (prediabetes) recommended by the
American Diabetes Association. Although 65 mg/dL is considered the 2.5 percentile, a fasting
level below 50 mg/dL is often seen without associated clinical hypoglycemia, and neonates
have a lower limit of approximately 40 mg/dL owing to maternal insulin
When preparing a patient for an oral glucose tolerance test (OGTT), which of the following
conditions will lead to erroneous results?
A. The patient remains ambulatory for 3 days prior to the test
B. Carbohydrate intake is restricted to below 150 g/day for 3 days prior to test
C. No food, coffee, tea, or smoking is allowed 8 hours before and during the test
D. Administration of 75 g of glucose is given to an adult patient following a 10-12-hour fast -
CORRECT ANSWER- ✔✔B. Carbohydrate intake is restricted to below 150 g/day for 3 days
prior to test
B Standardized OGTTs require that patients receive at least 150 grams of carbohydrate per
day for 3 days prior to the test in order to stabilize the synthesis of inducible glycolytic
enzymes. The 2-hour OGTT test is no longer recommended for screening and should be
reserved for confirmation of diabetes in cases that are difficult to diagnose, such as persons
who lack symptoms and signs of fasting hyperglycemia.
,Which of the following 2-hour glucose challenge results would be classified as impaired
glucose tolerance (IGT)?
Two-hour serum glucose:
A. 130 mg/dL
B. 135 mg/dL
C. 150 mg/dL
D. 204 mg/dL - CORRECT ANSWER- ✔✔C. 150 mg/dL
C With the exception of pregnant females, impaired glucose tolerance is defined by the ADA
as a serum or plasma glucose at 2 hours following a 75-g oral glucose load of ≥140 mg/dL
and < 200 mg/dL. Persons who have a fasting plasma glucose of ≥100 but < 126 mg/dL are
classified as having impaired fasting glucose (IFG). Both IGT and IFG are risk factors for
developing diabetes later in life. Such persons are classified as having prediabetes and should
be tested annually.
Which statement regarding gestational diabetes mellitus (GDM) is correct?
A. Is diagnosed using the same oral glucose tolerance criteria as in nonpregnancy
B. Converts to diabetes mellitus after pregnancy in 60%-75% of cases
C. Presents no increased health risk to the fetus
D. Is defined as glucose intolerance originating during pregnancy - CORRECT ANSWER-
✔✔D. Is defined as glucose intolerance originating during pregnancy
D Control of GDM reduces perinatal complications such as respiratory distress syndrome,
high birth weight, and neonatal jaundice. Women at risk are usually screened between 24 and
28 weeks' gestation. The screening test can be performed nonfasting and consists of an oral
50-g glucose challenge followed by serum or plasma glucose measurement at 1 hour. A result
≥ 140 mg/dL is followed by a 2-hour or 3-hour oral glucose tolerance test to confirm
gestational diabetes. For the 3-hour test, a 100-g dose of glucose is used and at least two of
the following cutoffs must be exceeded: fasting, ≥ 95 mg/dL or higher; 1 hour, ≥ 180 mg/dL
or higher; 2 hour ≥ 155 mg/dL or higher; 3 hour, ≥ 140 mg/dL or higher. The same cutpoints
are used for the 2-hour test except that a 75-g dose is used. GDM converts to diabetes
mellitus within 10 years in 30%-40% of cases. ADA recommends testing persons with GDM
for diabetes 6-12 weeks after delivery
, Which of the following findings is characteristic of all forms of clinical hypoglycemia?
A. A fasting blood glucose value below 55 mg/dL
B. High fasting insulin levels
C. Neuroglycopenic symptoms at the time of low blood sugar
D. Decreased serum C peptide - CORRECT ANSWER- ✔✔C Clinical hypoglycemia can be
caused by insulinoma, drugs, alcoholism, and reactive hypoglycemia. Neuroglycopenic
symptoms at the time of low blood sugar
C. Reactive hypoglycemia is characterized by delayed or excessive insulin output after eating
and is very rare. Fasting insulin is normal but postprandial levels are increased. High fasting
insulin levels (usually > 6 μg/L) are seen in insulinoma, and patients with insulinoma almost
always display fasting hypoglycemia, especially when the fast is extended to 48 72 hours. C
peptide is a subunit of proinsulin that is hydrolyzed when insulin is released. In
hypoglycemia, low levels indicate an exogenous insulin source, whereas high levels indicate
overproduction of insulin.
Which statement regarding glycated (glycosylated) Hgb (G-Hgb) is true?
A. Has a sugar attached to the C-terminal end of the β chain
B. Is a highly reversible aminoglycan
C. Reflects the extent of glucose regulation in the 8- to 12-week interval prior to sampling
D. Will be abnormal within 4 days following an episode of hyperglycemia - CORRECT
ANSWER- ✔✔C. Reflects the extent of glucose regulation in the 8- to 12-week interval prior
to sampling
C G-Hgb results from the nonenzymatic attachment of a sugar such as glucose to the N-
terminal valine of the β chain. The reaction is nonreversible and is related to the time-
averaged blood glucose concentration over the life span of the RBCs. There are three G-Hgb
fractions designated A1a, A1b, and Alc. Hemoglobin A1c makes up about 80% of glycated
hemoglobin, and is used to determine the adequacy of insulin therapy. The time-averaged
blood glucose is approximated by the formula (G-Hgb × 33.3) - 86 mg/dL, and insulin
adjustments can be made to bring this level to within reference limits. Also, glycated protein
assay (called fructosamine) provides similar data for the period between 2 and 4 weeks before
sampling.
