Clinical Chemistry: Carbohydrates (p.75-p.78)

Question 1

(p.77)

The glycated hemoglobin value represents the integrated values of glucose concentration during the preceding:

a) 1-3 weeks
b) 4-5 weeks
c) 6-8 weeks
d) 16-20 weeks

Answer 1

c) 6-8 weeks

Question 2

(p.77)

Which one of the following values obtained during a glucose tolerance test are diagnostic of diabetes mellitus?

a) 2-hour specimen = 150 mg/dL (8.3 mmol/L)
b) fasting plasma glucose = 126 mg/dL (6.9 mmol/L)
c) fasting plasma glucose = 110 mg/dL (6.1 mmol/L)
d) 2-hour specimen = 180 mg/dL (9.9 mmol/L)

Answer 2

b) fasting plasma glucose = 126 mg/dL (6.9 mmol/L)

Question 3

(p. 77)

In the fasting state, the arterial and capillary blood glucose concentration varies from the venous glucose concentration by approximately how many mg/dL (mmol/L)?

a) 1 mg/dL (0.05 mmol/L) higher
b) 5 mg/dL (0.27 mmol/L) higher
c) 10 mg/dL (0.55 mmol/L) lower
d) 15 mg/dL (0.82 mmol/L) lower

Answer 3

b) 5 mg/dL (0.27 mmol/L) higher

Question 4

(p.76)

If a fasting glucose was 90 mg/dL, which of the following 2-hour postprandial glucose results would most closely represent normal glucose metabolism?

a) 55 mg/dL (3.0 mmol/L)
b) 100 mg/dL (5.5 mmol/L)
c) 180 mg/dL (9.9 mmol/L)
d) 260 mg/dL (14.3 mmol/L)

Answer 4

b) 100 mg/dL (5.5 mmol/L)

Question 5

(p.77)

A patient with Type I, insulin-dependent diabetes mellitus has the following results:

Test | Patient | Reference Range

Fasting Blood Glucose | 150 mg/dL (8.3 mmol/L)
| 70-110 mg/dL (3.9/6.1 mmol/L) |

Hemoglobin A1C | 8.5% | 4.0%-6.0% |

Fructosamine | 2.5 mmol/L | 2.0-2.9 mmol/L

After reviewing these test results, the technologist concluded that the patient is in a:

a) “steady state” of metabolic control
b) state of flux, progressively worsening metabolic control
c) improving state of metabolic control as indicated by Fructosamine
d) state of flux as indicated by the fasting glucose level

Answer 5

c) improving state of metabolic control as indicated by Fructosamine

Question 6

(p.75)

The preparation of a patient for standard glucose tolerance testing should include:

a) a high carbohydrate diet for 3 days
b) a low carbohydrate diet for 3 days
c) fasting for 48 hours prior to testing
d) bed rest for 3 days

Answer 6

a) a high carbohydrate diet for 3 days

Question 7

(p.77)

Total glycosylated hemoglobin levels in a hemolysate reflect the:

a) average blood glucose levels of the past 2-3 months
b) average blood glucose levels for the past week
c) blood glucose level at the time the sample is drawn
d) hemoglobin A1C level at the time the sample is drawn

Answer 7

a) average blood glucose levels of the past 2-3 months

Question 8

(p.76)

Which of the following 2 hour postprandial glucose values demonstrates unequivocal hyperglycemic diagnostic for diabetes mellitus?

a) 160 mg/dL (8.8 mmol/L)
b) 170 mg/dL (9.4 mmol/L)
c) 180 mg/dL (9.9 mmol/L)
d) 200 mg/dL (11.0 mmol/L)

Answer 8

d) 200 mg/dL (11.0 mmol/L)

Question 9

(p. 75)

Following overnight fasting, hypoglycemia in adults is defined as a glucose of:

a) less than or equal to 70 mg/dL (less than or equal to 3.9 mmol/L)
b) less than or equal to 60 mg/dL (less than or equal to 3.3 mmol/L)
c) less than or equal to 55 mg/dL (less than or equal to 3.0 mmol/L)
d) less than or equal to 45 mg/dL (less than or equal to 2.5 mmol/L)

Answer 9

d) less than or equal to 45 mg/dL (less than or equal to 2.5 mmol/L)

Question 10

(p.76)

Cerebrospinal fluid for glucose assay should be:

a) refrigerated
b) analyzed immediately
c) heated to 56 °C
d) stored at room temperature after centrifugation

Answer 10

b) analyzed immediately

Question 11

(p.77)

Which of the following hemoglobins has glucose-6-phosphate on the amino-terminal valine of the beta chain?

a) S
b) C
c) A2
d) A1C

Answer 11

d) A1C

Question 12

(p.76)

A healthy person with a blood glucose of 80 mg/dL (4.4 mmol/L) would have a simultaneously determined cerebrospinal fluid glucose value of:

a) 25 mg/dL (1.4 mmol/L)
b) 50 mg/dL (2.3 mmol/L)
c) 100 mg/dL (5.5 mmol/L)
d) 150 mg/dL (8.3 mmol/L)

Answer 12

b) 50 mg/dL (2.3 mmol/L)

Question 13

(p. 76)

Pregnant women with symptoms of thirst, frequent urination or unexplained weight loss should have which of the following tests performed?

a) tolbutamide test
b) lactose tolerance test
c) epinephrine tolerance test
d) glucose tolerance test

Answer 13

d) glucose tolerance test

Question 14

(p.77)

Monitoring long-term glucose control in patients with adult onset diabetes mellitus can best be accomplished by measuring:

a) weekly fasting 7 am serum glucose
b) glucose tolerance testing
c) 2-hour postprandial serum glucose
d) hemoglobin A1C

Answer 14

d) hemoglobin A1C

Question 15

(p. 76)

A 25 year-old man became nauseated and vomited 90 minutes after receiving a standard 75 g carbohydrate dose for an oral glucose tolerance test. The best course of action is to:

a) give the patient a glass of orange juice and continue the test
b) start the test over immediately with a 50 g carbohydrate dose
c) draw blood for glucose and discontinue test
d) place the patient in a recumbent position, reassure him and continue the test

Answer 15

c) draw blood for glucose and discontinue test

Question 16

(p.76)

Serum levels that define hypoglycemia in pre-term or low birth weight infants are:

a) the same as adults
b) lower than adults
c) the same as a normal full-term infant
d) higher than a normal full-term infant

Answer 16

b) lower than adults

Question 17

(p.75)

The following results are from a 21-year-old patient with a back injury who appears otherwise healthy:
whole blood glucose: 77 mg/dL (4.2 mmol/L)
serum glucose: 88 mg/dL (4.8 mmol/L)
CSF glucose: 56 mg/dL (3.1 mmol/L)

The best interpretation of these results is that:

a) the whole blood and the serum values are expected but the CSF value is elevated
b) the whole blood glucose value should be higher than the serum value
c) all values are consistent with a normal healthy individual
d) the serum and whole blood values should be identical

Answer 17

c) all values are consistent with a normal healthy individual

Question 18

(p. 77)

The conversion of glucose or other hexoses into lactate or pyruvate is called:

a) glycogenesis
b) glycogenolysis
c) gluconeogenesis
d) glycolysis

Answer 18

d) glycolysis

Question 19

(p.76)

A 45-year-old woman has a fasting serum glucose concentration of 95 mg/dL (5.2 mmol/L) and a 2-hour postprandial glucose concentration of 105 mg/dL (5.8 mmol/L). The statement which best describes this patient’s fasting serum glucose concentration is:

a) normal; reflecting glycogen breakdown by the liver
b) normal; reflecting glycogen breakdown by skeletal muscle
c) abnormal; indicating diabetes mellitus
d) abnormal; indicating hypoglycemia

Answer 19

a) normal; reflecting glycogen breakdown by the liver

Question 20

A patient with hemolytic anemia will:

a) show a decrease in glycated Hgb value
b) show an increase in glycated Hgb value
c) show little or no change in glycated Hgb value
d) demonstrate an elevated Hgb A1C

Answer 20

a) show a decrease in glycated Hgb value

Question 21

In using ion-exchange chromatographic methods, falsely increased levels of Hgb A1C might be demonstrated in the presence of:

a) iron deficiency anemia
b) pernicious anemia
c) thalassemias
d) Hgb S

Answer 21

d) Hgb S

Question 22

An increase in serum acetone is indicative of a defect in the metabolism of:

a) carbohydrates
b) fat
c) urea nitrogen
d) uric acid

Answer 22

a) carbohydrates

Question 23

An infant with diarrhea is being evaluated for a carbohydrate intolerance. His stool yields a positive copper reduction test and a pH of 5.0. It should be concluded that:

a) further tests are indicated
b) results are inconsistent - repeat both tests
c) the diarrhea is not due to carbohydrate intolerance
d) the tests provided no useful information

Answer 23

a) further tests are indicated

Question 24

Blood samples were collected at the beginning of an exercise class and after thirty minutes of aerobic activity. Which of the following would be most consistent with the poet-exercise sample?

a) normal lactic acid, low pyruvate
b) low lactic acid, elevated pyruvate
c) elevated lactic acid, low pyruvate
d) elevated lactic acid, elevated pyruvate

Answer 24

d) elevated lactic acid, elevated pyruvate

Question 25

What is the best method to diagnose lactase deficiency?

a) H2 breath test
b) plasma aldolase level
c) LDH level
d) D-xylose test

Answer 25

a) H2 breath test