Carbohydrates (Harr) Flashcards

Question 1

Q

Which of the following biochemical processes is
promoted by insulin?
A. Glycogenolysis
B. Gluconeogenesis
C. Lipolysis
D. Uptake of glucose by cells

Question 2

Q

Which of the following hormones promotes
hyperglycemia?
A. Calcitonin
B. Growth hormone
C. Aldosterone
D. Renin

Question 3

Q

Which of the following is characteristic of
type 1 diabetes mellitus?
A. Requires an oral glucose tolerance test for
diagnosis
B. Is the most common form of diabetes mellitus
C. Usually occurs after age 40
D. Requires insulin replacement to prevent ketosis

Question 4

Q

Which of the following is characteristic of
type 2 diabetes mellitus?
A. Insulin levels are consistently low
B. Most cases require a 3-hour oral glucose
tolerance test to diagnose
C. Hyperglycemia is often controlled without
insulin replacement
D. The condition is associated with unexplained
weight loss

Question 5

Q

Which of the following results falls within the
diagnostic criteria for diabetes mellitus?
A. Fasting plasma glucose of 120 mg/dL
B. Two-hour postprandial plasma glucose of
160 mg/dL
C. Two-hour plasma glucose of 180 mg/dL
following a 75 g oral glucose challenge
D. Random plasma glucose of 250 mg/dL and
presence of symptoms

Question 6

Q

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)

Question 7

Q

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

Question 8

Q

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

Question 9

Q

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

Question 10

Q

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

Question 11

Q

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

Question 12

Q

What is the American Diabetes Association
recommended cutoff value for adequate control of
blood glucose in diabetics as measured by glycated
hemoglobin?
A. 5%
B. 6.5%
C. 9.5%
D. 11%

Question 13

Q

Which statement regarding measurement of Hgb
A1c is true?
A. Levels do not need to be done fasting
B. Both the labile and stable Hgb A1c fractions are
measured
C. Samples should be measured within 2 hours of
collection
D. The assay must be done by chromatography

Question 14

Q

Which stationary phase is used for the
measurement of hemoglobin A1c by high
performance liquid chromatography?
A. Octadecylsilane (C18)
B. Cation exchanger
C. Anion exchanger
D. Polystyrene divinylbenzene

Question 15

Q

Evaluate the following chromatogram of a
whole-blood hemolysate, and identify the cause
and best course of action.
A. Result is not reportable because hemoglobin F
is present and interferes
B. The result is not reportable because
hemoglobin C is present and interferes
C. The result is not reportable because labile
hemoglobin A1c is present
D. The result is reportable; neither hemoglobin F
or C interfere

Question 16

Q

According to American Diabetes Association
criteria, which result is consistent with a diagnosis
of impaired fasting glucose?
A. 99 mg/dL
B. 117 mg/dL
C. 126 mg/dL
D. 135 mg/dL

Question 17

Q

What is the recommended cutoff for the early
detection of chronic kidney disease in diabetics
using the test for microalbuminuria?
A. >30 mg/g creatinine
B. >80 mg/g creatinine
C. >200 mg/g creatinine
D. >80 mg/L

Question 18

Q

In addition to measuring blood glucose, Hgb A1c,
and microalbumin, which test should be done on
diabetic persons once per year?
A. Urine glucose
B. Urine ketones
C. Plasma fructosamines
D. Estimated glomerular filtration rate

Question 19

Q

Which testing situation is appropriate for the use
of point-of-care whole-blood glucose methods?
A. Screening for type 2 diabetes mellitus
B. Diagnosis of diabetes mellitus
C. Monitoring of blood glucose control in type 1
and type 2 diabetics
D. Monitoring diabetics for hyperglycemic
episodes only

Question 20

Q

Which of the following is the reference method
for measuring serum glucose?
A. Somogyi–Nelson
B. Hexokinase
C. Glucose oxidase
D. Glucose dehydrogenase

Question 21

Q

Polarographic methods for glucose analysis are
based upon which principle of measurement?
A. Nonenzymatic oxidation of glucose
B. The rate of O2 depletion
C. Chemiluminescence caused by formation of
adenosine triphosphate (ATP)
D. The change in electrical potential as glucose is
oxidized

Question 22

Q

In addition to polarography, what other
electrochemical method can be used to
measure glucose in plasma?
A. Conductivity
B. Potentiometry
C. Anodic stripping voltammetry
D. Amperometry

Question 23

Q

Select the enzyme that is most specific for
β-D-glucose.
A. Hexokinase
B. G-6-PD
C. Phosphohexisomerase
D. Glucose oxidase

Question 24

Q

Select the coupling enzyme used in the hexokinase
method for glucose.
A. Glucose-6-phosphate dehydrogenase
B. Peroxidase
C. Glucose dehydrogenase
D. Glucose-6-phosphatase

Question 25

Q

Which glucose method is subject to falsely low
results caused by ascorbate?
A. Hexokinase
B. Glucose dehydrogenase
C. Trinder glucose oxidase
D. Polarography

Question 26

Q

Which of the following is a potential source
of error in the hexokinase method?
A. Galactosemia
B. Hemolysis
C. Sample collected in fluoride
D. Ascorbic acid

Question 27

Q

Which statement about glucose in cerebrospinal
fluid (CSF) is correct?
A. Levels below 40 mg/dL occur in septic
meningitis, cancer, and multiple sclerosis
B. CSF glucose is normally the same as the plasma
glucose level
C. Hyperglycorrhachia is caused by dehydration
D. In some clinical conditions, the CSF glucose can
be greater than the plasma glucose

Question 28

Q

In peroxidase-coupled glucose methods, which
reagent complexes with the chromogen?
A. Nitroprusside
B. Phenol
C. Tartrate
D. Hydroxide

Question 29

Q

Point-of-care-tests (POCTs) for whole-blood
glucose monitoring are based mainly on the use of:
A. Glucose oxidase as the enzyme
B. Amperometric detection
C. Immunochromatography
D. Peroxidase coupling reactions

Question 30

Q

What effect does hematocrit have on POCT tests
for whole-blood glucose monitoring?
A. Low hematocrit decreases glucose readings on all
devices
B. High hematocrit raises glucose readings on all
devices
C. The effect is variable and dependent on the
enzyme/coenzyme system
D. Low hematocrit raises readings and high
hematocrit lowers readings unless corrected

Question 31

Q

Which of the following is classified as a
mucopolysaccharide storage disease?
A. Pompe’s disease
B. von Gierke disease
C. Hers’ disease
D. Hurler’s syndrome

Question 32

Q

Identify the enzyme deficiency responsible for type
1 glycogen storage disease (von Gierke’s disease).
A. Glucose-6-phosphatase
B. Glycogen phosphorylase
C. Glycogen synthetase
D. β-Glucosidase

Question 33

Q

Which of the following abnormal laboratory
results is found in von Gierke’s disease?
A. Hyperglycemia
B. Increased glucose response to epinephrine
administration
C. Metabolic alkalosis
D. Hyperlipidemia

Question 34

Q

The D-xylose absorption test is used for the
differential diagnosis of which two diseases?
A. Pancreatic insufficiency from malabsorption
B. Primary from secondary disorders of glycogen
synthesis
C. Type 1 and type 2 diabetes mellitus
D. Generalized from specific carbohydrate
intolerance

Question 35

Q

Which of the following statements about
carbohydrate intolerance is true?
A. Galactosemia results from deficiency of
galactose-1-phosphate (galactose-1-PO4)
uridine diphosphate transferase
B. Galactosemia results in a positive glucose oxidase
test for glucose in urine
C. Urinary galactose is seen in both galactosemia
and lactase deficiency
D. A galactose tolerance test is used to confirm a
diagnosis of galactosemia

Question 36

Q

Which of the following statements regarding iron
metabolism is correct?
A. Iron absorption is decreased by alcohol ingestion
B. Normally, 40%–50% of ingested iron is
absorbed
C. The daily requirement is higher for pregnant and
menstruating women
D. Absorption increases with the amount of iron in
the body stores

Question 37

Q

Which of the following processes occurs when iron
is in the oxidized (Fe3+) state?
A. Absorption by intestinal epithelium
B. Binding to transferrin and incorporation into
ferritin
C. Incorporation into protoporphyrin IX to form
functional heme
D. Reaction with chromogens in colorimetric assays

Question 38

Q

Which of the following is associated with
low serum iron and high total iron-binding
capacity (TIBC)?
A. Iron deficiency anemia
B. Hepatitis
C. Nephrosis
D. Noniron deficiency anemias

Question 39

Q

Which condition is associated with the lowest
percent saturation of transferrin?
A. Hemochromatosis
B. Anemia of chronic infection
C. Iron deficiency anemia
D. Noniron deficiency anemia

Question 40

Q

Which condition is most often associated with a
high serum iron level?
A. Nephrosis
B. Chronic infection or inflammation
C. Polycythemia vera
D. Noniron deficiency anemias

Question 41

Q

Which of the following is likely to occur first in
iron deficiency anemia?
A. Decreased serum iron
B. Increased TIBC
C. Decreased serum ferritin
D. Increased transferrin

Question 42

Q

Which formula provides the best estimate of
serum TIBC?
A. Serum transferrin in mg/dL × 0.70 = TIBC
(μg/dL)
B. Serum transferrin in mg/dL × 1.43 = TIBC
(μg/dL)
C. Serum iron (μg/dL)/1.2 + 0.06 = TIBC (μg/dL)
D. Serum Fe (μg/dL) × 1.25 = TIBC (μg/dL)

Question 43

Q

Which statement regarding the diagnosis of iron
deficiency is correct?
A. Serum iron levels are always higher at night than
during the day
B. Serum iron levels begin to fall before the body
stores become depleted
C. A normal level of serum ferritin rules out iron
deficiency
D. A low serum ferritin is diagnostic of iron
deficiency

Question 44

Q

Which statement about iron methods is true?
A. Interference from Hgb can be corrected by a
serum blank
B. Colorimetric methods measure binding of Fe2+
to a ligand such as ferrozine
C. Atomic absorption is the method of choice for
measurement of serum iron
D. Serum iron can be measured by potentiometry

Question 45

Q

Which of the following statements regarding the
TIBC assay is correct?
A. All TIBC methods require addition of excess
iron to saturate transferrin
B. All methods require the removal of unbound
iron
C. Measurement of TIBC is specific for transferrinbound iron
D. The chromogen used must be different from the
one used for measuring serum iron

Question 46

Q

Which of the following statements regarding the
metabolism of bilirubin is true?
A. It is formed by hydrolysis of the α methene
bridge of urobilinogen
B. It is reduced to biliverdin prior to excretion
C. It is a by-product of porphyrin production
D. It is produced from the destruction of RBCs

Question 47

Q

Bilirubin is transported from reticuloendothelial
cells to the liver by:
A. Albumin
B. Bilirubin-binding globulin
C. Haptoglobin
D. Transferrin

Question 48

Q

In the liver, bilirubin is conjugated by addition of:
A. Vinyl groups
B. Methyl groups
C. Hydroxyl groups
D. Glucuronyl groups

Question 49

Q

Which enzyme is responsible for the conjugation
of bilirubin?
A. β-Glucuronidase
B. UDP-glucuronyl transferase
C. Bilirubin oxidase
D. Biliverdin reductase

Question 50

Q

The term δ-bilirubin refers to:
A. Water-soluble bilirubin
B. Free unconjugated bilirubin
C. Bilirubin tightly bound to albumin
D. Direct-reacting bilirubin

Question 51

Q

Which of the following processes is part of the
normal metabolism of bilirubin?
A. Both conjugated and unconjugated bilirubin are
excreted into the bile
B. Methene bridges of bilirubin are reduced by
intestinal bacteria forming urobilinogens
C. Most of the bilirubin delivered into the intestine
is reabsorbed
D. Bilirubin and urobilinogen reabsorbed from the
intestine are mainly excreted by the kidney

Question 52

Q

Which of the following is a characteristic of
conjugated bilirubin?
A. It is water soluble
B. It reacts more slowly than unconjugated
bilirubin
C. It is more stable than unconjugated bilirubin
D. It has the same absorbance properties as
unconjugated bilirubin

Question 53

Q

Which of the following statements regarding
urobilinogen is true?
A. It is formed in the intestines by bacterial
reduction of bilirubin
B. It consists of a single water-soluble bile
pigment
C. It is measured by its reaction with
p-aminosalicylate
D. In hemolytic anemia, it is decreased in urine
and feces

Question 54

Q

Which statement regarding bilirubin metabolism
is true?
A. Bilirubin undergoes rapid photo-oxidation when
exposed to daylight
B. Bilirubin excretion is inhibited by barbiturates
C. Bilirubin excretion is increased by
chlorpromazine
D. Bilirubin is excreted only as the diglucuronide

Question 55

Q

Which condition is caused by deficient secretion of
bilirubin into the bile canaliculi?
A. Gilbert’s disease
B. Neonatal hyperbilirubinemia
C. Dubin–Johnson syndrome
D. Crigler–Najjar syndrome

Question 56

Q

In hepatitis, the rise in serum conjugated bilirubin
can be caused by:
A. Secondary renal insufficiency
B. Failure of the enterohepatic circulation
C. Enzymatic conversion of urobilinogen to
bilirubin
D. Extrahepatic conjugation

Question 57

Q

Which of the following is a characteristic of
obstructive jaundice?
A. The ratio of direct to total bilirubin is greater
than 1:2
B. Conjugated bilirubin is elevated, but
unconjugated bilirubin is normal
C. Urinary urobilinogen is increased
D. Urinary bilirubin is normal

Question 58

Q

Which of the following would cause an increase
in only the unconjugated bilirubin?
A. Hemolytic anemia
B. Obstructive jaundice
C. Hepatitis
D. Hepatic cirrhosis

Question 59

Q

Which form of hyperbilirubinemia is caused by an
inherited absence of UDP-glucuronyl transferase?
A. Gilbert’s syndrome
B. Rotor syndrome
C. Crigler–Najjar syndrome
D. Dubin–Johnson syndrome

Question 60

Q

Which statement regarding total and direct
bilirubin levels is true?
A. Total bilirubin level is a less sensitive and specific
marker of liver disease than the direct level
B. Direct bilirubin exceeds 3.5 mg/dL in most cases
of hemolytic anemia
C. Direct bilirubin is normal in cholestatic liver
disease
D. The ratio of direct to total bilirubin exceeds 0.40
in hemolytic anemia

Question 61

Q

Which statement best characterizes serum
bilirubin levels in the first week following delivery?
A. Serum bilirubin 24 hours after delivery should
not exceed the upper reference limit for adults
B. Jaundice is usually first seen 48–72 hours
postpartum in neonatal hyperbilirubinemia
C. Serum bilirubin above 5.0 mg/dL occurring
2–5 days after delivery indicates hemolytic or
hepatic disease
D. Conjugated bilirubin accounts for about 50% of
the total bilirubin in neonates

Question 62

Q

Which form of jaundice occurs within days of
delivery and usually lasts 1–3 weeks, but is not
due to normal neonatal hyperbilirubinemia or
hemolytic disease of the newborn?
A. Gilbert syndrome
B. Lucey –Driscoll syndrome
C. Rotor syndrome
D. Dubin–Johnson syndrome

Question 63

Q

A lab measures total bilirubin by the
Jendrassik–Grof bilirubin method with sample
blanking. What would be the effect of moderate
hemolysis on the test result?
A. Falsely increased due to optical interference
B. Falsely increased due to release of bilirubin
from RBCs
C. Falsely low due to inhibition of the diazo
reaction by hemoglobin
D. No effect due to correction of positive
interference by sample blanking

Question 64

Q

Which reagent is used in the Jendrassik–Grof
method to solubilize unconjugated bilirubin?
A. 50% methanol
B. N-butanol
C. Caffeine
D. Acetic acid

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Carbohydrates (Harr) Flashcards

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