U2.1 Intro to Carbohydrates and Glucose Determination [L]

Question 1

Major food source and energy supply for the body

Answer 1

Carbohydrates

Question 2

Carbohydrates is stored primarily at the _____ & ______

Answer 2

liver and muscle glycogen

Question 3

2 Main Diseases of Carbohydrates

Answer 3

Hyperglycemia and hypoglycemia

Question 4

2 Major Hormones

Answer 4

Insulin & Glucagon

Question 5

Primary hormone responsible for the entry of glucose into the cell

Answer 5

Insulin

Question 6

Decreases plasma glucose levels.

Answer 6

Insulin

Question 7

Regulates glucose by increasing glycogenesis, lipogenesis, and glycolysis and inhibiting glycogenolysis

Answer 7

Insulin

Question 8

Primary hormone responsible for increasing glucose levels.

Answer 8

Glucagon

Question 9

Increases plasma glucose levels by glycogenolysis and gluconeogenesis

Answer 9

Glucagon

Question 10

Measured routinely using serum or plasma

Answer 10

Glucose

Question 11

Specimen for glucose

Answer 11

whole blood, urine, CSF, and other body fluids

Question 12

T/F Whole blood glucose is approx. 11% lower than serum or plasma glucose

Answer 12

T

Question 13

T/F Venous blood glucose is approx. 5 mg/dL lower than capillary blood due to tissue metabolism

Answer 13

F, 7 mg/dL lower than capillary blood

Question 14

T/F CSF glucose levels is approx. 60-70% plasma glucose levels

Answer 14

T

Question 15

sample obtained for FBG is collected during

Answer 15

morning

Question 16

T/F Fasting plasma glucose has diurnal variation: ↑ AM than in PM

Answer 16

T

Question 17

hrs of fasting for FBS

Answer 17

8-10 hrs fasting, not longer than 16 hrs

Question 18

T/F Serum or plasma should be separated from the cells ASAP

Answer 18

T

Question 19

Glucose

_____ lowers the glucose levels in an uncentrifuged blood specimen

Answer 19

Glycolysis

Question 20

Glucose

Room temperature

Answer 20

decrease 5-10 mg/dL (5-7%) per hour

Question 21

Glucose

Refrigerated temperature

Answer 21

approx. 2 mg/dL per hour

Question 22

Tube used to inhibit vitro glycolysis

Answer 22

Sodium fluoride tube (gray top)

Question 23

T/F Gray top is stable for up to 3 days at room temperature

Answer 23

T

Question 24

2 Main Methods of Glucose Determination

Answer 24

1. Enzymatic
2. Non-enzymatic

Question 25

Enzymatic Methods (3)

Answer 25

1. Glucose oxidase 2. Hexokinase 3. Glucose dehydrogenase

Question 26

Non-enzymatic methods (3)

Answer 26

1. Alkaline copper reduction method 2. Alkaline ferric reduction method 3. Condensation method

Question 27

Methods of Glucose Determination Principle: Reduction of cupric ions to cuprous ions forming cuprous oxide in hot alkaline solution by glucose

Answer 27

Alkaline Copper Reduction Method

Question 28

Alkaline Copper Reduction Method - Glucose + alk. cupric tartrate → CuOH + heat → cuprous oxide - Cu2O + arsenomolybdic acid → arsenomolybdenum blue

Answer 28

Nelson Somogyi Method

Question 29

Alkaline Copper Reduction Method Reaction : - Glucose + alk. cupric tartrate → CuOH + heat → cuprous oxide - Cu2O + phosphomolybdic acid → phosphomolybdenum blue

Answer 29

Folin Wu Method

Question 30

Alkaline Copper Reduction Method Reaction : - Glucose + alk. cupric-neocuproine → Cuprous-neocuproine complex End color: yellow to yellow-orange

Answer 30

Neocuproine Method

Question 31

Alkaline Copper Reduction Method Reaction : - Glucose + CuSO4 (blue) + heat → Cu2O - Uses tartrate & citrate as stabilizing agent

Answer 31

Benedict’s Method

Question 32

Alkaline Copper Reduction Method End color: green → yellow → orange → brick red

Answer 32

Benedict's Method

Question 33

Methods of Glucose Determination Principle: Reduction of ferricyanide to ferrocyanide in hot alkaline solution by glucose

Answer 33

Alkaline Ferric Reduction Method

Question 34

Alkaline Ferric Reduction Method Reaction : - Glucose + [Fe(CN)6]3− (yellow) in alk soln + heat → [Fe(CN)6]4− (colorless) - Inverse colorimetry

Answer 34

Hagedorn Jensen Method

Question 35

Alkaline Ferric Reduction Method End color of Hagedorn Jensen Method

Answer 35

colorless

Question 36

Methods of Glucose Determination Principle: Ability of primary aromatic amine acid solution to condense with the aldehyde group of glucose to form glucosylamines (Schiff bases)

Answer 36

Condensation Method

Question 37

Methods of Glucose Determination Formed when aldehyde group of glucose forms glucosylamines

Answer 37

Schiff bases

Question 38

Condensation Method Reaction : - Glucose + o-toluidine + acetic acid + heat → N-glucosylamine

Answer 38

Ortho-toluidine (Dubowski method)

Question 39

Condensation Method End color of Ortho-toluidine (Dubowski method)

Answer 39

bluish green

Question 40

Also called Saifer Gernstenfield method

Answer 40

Glucose Oxidase Method

Question 41

Enzymatic Methods Reaction : Step 1: Mutarotase catalyzes mutarotation of α- to β-glucose * Step 2 & 3: Trinder reaction – couple reaction

Answer 41

Glucose Oxidase Method

Question 42

Enzymatic Methods Also called Saifer Gernstenfield method

Answer 42

Glucose Oxidase Method

Question 43

Enzymatic Methods Considered as the reference method for blood glucose determination

Answer 43

Hexokinase Method

Question 44

Enzymatic Methods Principle - Glucose + ATP > glucose-6-phosphate + ADP - Glucose-6-phosphate + NADP+ > NADPH + H+ + 6-phosphogluconate

Answer 44

Hexokinase Method

Question 45

Enzymatic Methods Principle: 1. α-D-glucose > β-D-glucose 2. β-D-glucose + NAD > gluconolactone + NADH 3. NADH + MTT > Formazan (blue)+ H2O - MTT: tetrazolium bromide salt (colorless)

Answer 45

Glucose Dehydrogenase Method

Question 46

Glucose Oxidase Method Glucose Oxidase Method is read on the assay requirements : 1. Wavelength 2. Optical path 3. Temperature 4. Measurement

Answer 46

1. Wavelength: 500 nm 2. Optical path: 1 cm 3. Temperature: 37°C 4. Measurement: Read against reagent blank

Question 47

Reference values and expected ranges of controls Reference Values : conventional unit

Answer 47

Conventional unit = 70-110 mg/dL

Question 48

Reference values and expected ranges of controls SI Unit

Answer 48

SI unit = 3.9-6.1 mmol/L

Question 49

Reference values and expected ranges of controls Conversion factor (mg/dL → mmol/L)

Answer 49

0.0556

Question 50

Expected Ranges of Controls Elitrol I (normal control)

Answer 50

80.0 – 108.2 mg/dL 4.44 – 6.00 mmol/L

Question 51

Expected Ranges of Controls Elitrol II (pathologic control)

Answer 51

215.2 – 291.2 mg/dL 11.94 – 16.16 mmol/L

Question 52

Clinical Significance Increased glucose leads to:

Answer 52

DM, pancreatitis, pituitary thyroid dysfunction, renal failure, liver disease

Question 53

Clinical significance Decreased glucose leads to :

Answer 53

starvation, hyperinsulinemia, insulin-induced hypoglycemia, neoplasms

Question 54

Hypothetical readings : Accept or Reject CN (N) = 93.33 mg/dL CN (P) = 283.33 mg/dL

Answer 54

Accept both

Question 55

Hypothetical readings : Accept or Reject Unkown = 76.67 mg/dL

Answer 55

Accept; normal