Glucose Flashcards

1
Q

SPECIMEN CONSIDERATIONS

PCWPUS

A

-Whole blood
-Plasma
-CSF
-Pleural Fluid
-Urine
-Serum

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2
Q

15% lower than serum or plasma

A

Whole blood

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3
Q

Unhemolyzed Venous plasma/serum

A

Serum

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4
Q

Separation of liquid portion

A

• Serum be separated within 30 minutes
• Serum w/o bacterial contamination & w/o leukocytosis (^WBC) = up to 90 minutes delay
• Plasma must be separated from the cellular fraction (even with Na fluoride)

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5
Q

Separation of liquid portion
• Serum be separated within____

A

30 minutes

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6
Q

Separation of liquid portion

• Serum w/o bacterial contamination & w/o leukocytosis (^WBC) = up to_____ delay

A

90 minutes

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7
Q

Separation of liquid portion

• Plasma must be separated from the______ (even with Na fluoride)

A

cellular fraction

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8
Q

is the process in which glucose is broken down to produce energy.

It produces two molecules of pyruvate, ATP, NADH and water.

The process takes place in the cytoplasm of a cell and does not require oxygen.

A

Glycolysis

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9
Q

______ decreases serum glucose by approximately 5% to 7% in 1 hour (5 to 10 mg/L) in normal uncentrifuged coagulated blood at room temperature.

A

Glycolysis

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10
Q

Glycolysis decreases serum glucose by approximately _____ to ____ in 1 hour (___ to ___mg/L) in normal uncentrifuged coagulated blood at room temperature.

A

5% to 7%

5 to 10 mg/L

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11
Q

Specimen for Glucose

In separated , nonhemolyzed sterile serum, stable as long as ___ hours at 25°C an up to___ hours at 4°C

A

8 hrs

72hrs

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12
Q

Specimen consideration

Storage of samples

•Refrigerated (____)
–serum or plasma: stable up to____ hrs

–Whole blood:____mg Na fluoride per mL of whole blood (___hrs)

A

2-8ºC

48 hrs

2mg

48 hrs

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13
Q

GLUCOSE METHODOLOGIES

A

CHEMICAL Method

ENZYMATIC Method

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14
Q

CHEMICAL METHOD

A

Oxidation reduction method
Condensation method

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15
Q

Oxidation Reduction Method (2)

AC
AF

A

Alkaline Copper Reduction Method

Alkaline Ferric Reduction Method

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16
Q

Alkaline Copper Reduction Method

A

a. Folin Wu Method
b. Nelson Somogyi Method
c. Neocuproine Method
d. Benedict’s Method

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17
Q

(Modification of Folin Wu)

A

Benedict’s Method

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18
Q

Alkaline Ferric Reduction Method

A

Hagedorn Jensen

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19
Q

CONDENSATION METHOD

A

Dubowski Method

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20
Q

Reduction of cupric ions to cuprous ions forming cuprous oxide in hot alkaline solution by glucose.

A

Alkaline Copper Reduction Method

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21
Q

Alkaline Copper Reduction Method

Principle:

Reduction of cupric ions to cuprous ions forming________ in _______ solution by glucose.

A

cuprous oxide

* hot alkaline solution*

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22
Q

Alkaline Copper Reduction Method

Cuprous Ions + Phosphomolybdate

Phosphomolybdic Acid or Phosphomolybdenum Blue

A

Folin Wu Method

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23
Q

Alkaline Copper Reduction Method

Cuprous Ions + Arsenomolybdate

Arsenomolybdic Acid or Arsenomolybdenum Blue

A

Nelson Somogyi Method

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24
Q

Alkaline Copper Reduction Method

(2,9 Dimethyl 1,10 Phenantroline Hydrochloride)

Cuprous Ions + Neocuproine

Cuprous-Neocuproine Complex (Yellow or Yellow Orange)

A

Neocuproine Method

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25
Q

Alkaline Copper Reduction Method

used for detection and quantitation of reducing substances in body fluids like blood and urine.

A

Benedict’s Method (Modification of Folin-Wu)

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26
Q

stabilizing agent in Benedict’s method

A

citrate or tartrate

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27
Q

Folin Wu Method

Product

A

Phosphomolybdic Acid or Phosphomolybdenum Blue

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28
Q

Nelson Somogyi Method

Product

A

Arsenomolybdic Acid or Arsenomolybdenum Blue

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29
Q

Neocuproine Method

Product

A

Cuprous-Neocuproine Complex
(Yellow or Yellow Orange)

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30
Q

Benedict’s

None

A

Blue solution

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31
Q

Benedict’s

Traces of reducing sugar

A

Green / yellow ppt

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32
Q

Benedict’s

Moderate

A

Orange red ppt

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33
Q

Benedict’s

Large amount of reducing sugar

A

Brick-red ppt

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34
Q

OXIDATION REDUCTION METHOD

Alkaline Ferric Reduction Method by ______

A

(Hagedorn Jensen)

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35
Q

It involves reduction of a yellow ferricyanide to a colorless ferrocyanide by glucose (Inverse Colorimetry)

A

Alkaline Ferric Reduction Method

36
Q

Alkaline Ferric Reduction Method

It involves reduction of a yellow ferricyanide to a ______ by glucose

A

colorless ferrocyanide

37
Q

(Inverse Colorimetry)

A

Alkaline Ferric Reduction Method

38
Q

CHEMICAL METHOD

•condensation of glucose with a primary aromatic amine in glacial acetic acid, forming an equilibrium mixture of a glycosylamine and the corresponding Schiff base

A

Condensation Method

Ortho-toluidine (Dubowski Method)

39
Q

CHEMICAL METHOD

B. Condensation Method

Ortho-toluidine (Dubowski Method)

•Procedure:

–Glucose in a PFF (3% TCA) reacts to O-Toluidine in hot______ solution will yield a_____ colored compound with maximum absorbance at______nm

A

acidic

GREEN

630 nm

40
Q

ENZYMATIC METHODS

A
  1. GLUCOSE OXIDASE METHOD
  2. HEXOKINASE METHOD
  3. GLUCOSE DEHYDROGENASE METHOD
  4. DEXTROSTICS (cellular strip)
  5. INTERSTITIAL GLUCOSE MEASURING DEVICE
41
Q
  1. GLUCOSE OXIDASE METHOD (2)
A

a. Colorimetric Glucose Oxidase Method (Saifer Gerstenfield Method)

b. Polarographic Glucose Oxidase

42
Q

+Colorimetric Glucose Oxidase Method* (Saifer Gernstenfield Method)

  1. Increased levels of (3) can cause falsely decreased values as a result of these substances being oxidized by peroxidase, which then prevents the oxidation and detection of the chromogen.
  2. Strong oxidizing substances, such as____, can cause falsely increased values
A

uric acid, bilirubin, and ascorbic acid

bleach

43
Q

GLUCOSE OXIDASE METHOD

Measures rate of oxygen consumption which is proportional to glucose concentration.

A

Polarographic Glucose Oxidase

44
Q

Polarographic Glucose Oxidase

______ in the reagent catalyzes the oxidation of glucose by oxygen under first order conditions, forming hydrogen peroxide.

Quantitated by the consumption of oxygen on an_______

A

Glucose oxidase

oxygen-sensing electrode

45
Q

Polarographic Glucose Oxidase

_______is prevented from re-forming oxygen by adding molybdate, iodide, catalase and ethanol.

A

Hydrogen peroxide

46
Q

ENZYMATIC METHODS

MOST SPECIFIC GLUCOSE METHOD; REFERENCE METHOD

Less interference Plasma collected using heparin, EDTA, flouride, oxalate or citrate may be used for this test.

Other samples; Urine, CSF and serous fluids

A

HEXOKINASE METHOD

47
Q

ENZYMATIC METHODS

HEXOKINASE METHOD

Gross hemolysis and extremely elevated bilirubin may cause a _____ in results.

A

false decrease

48
Q

ENZYMATIC METHODS

Glucose is reduced to produce a chromophore that is measured spectrophotometrically or an electrical current NADH = glucose concentration

Close agreement with hexokinase procedures

________ is added to shorten the time

A

GLUCOSE DEHYDROGENASE METHOD

Mutarotose

49
Q

ENZYMATIC METHODS

GLUCOSE DEHYDROGENASE METHOD

Glucose is reduced to produce a______ that is measured spectrophotometrically or an electrical current

NADH =______

Close agreement with hexokinase procedures

_____is added to shorten the time

A

chromophore

glucose concentration

Mutarotose

50
Q

ENZYMATIC METHODS

An enzyme-impregnated strip used with a small portable electronic colour-measuring device for convenient estimation of the blood sugar levels by diabetics.

A

DEXTROSTICS (cellular strip)

51
Q

ENZYMATIC METHODS

DEXTROSTICS (cellular strip)

An________ used with a small portable electronic colour-measuring device for convenient estimation of the blood sugar levels by diabetics.

A

enzyme-impregnated strip

52
Q

It should not be used to diagnose diabetes or hypoglycemic disorders.

A

DEXTROSTICS (cellular strip)

53
Q

ENZYMATIC METHODS

-used for cobtinuous monitoring of glucose levels in people with diabetes

A

INTERSTITIAL GLUCOSE MEASURING DEVICE

54
Q

ENZYMATIC METHODS

-uses electrochemical methods to automatically and frequently measure glucose levels in the interstitial fluid of dermis or subcutaneous fat tissue.

A

INTERSTITIAL GLUCOSE MEASURING DEVICE

55
Q

ENZYMATIC METHODS

INTERSTITIAL GLUCOSE MEASURING DEVICE

-used for continuous monitoring of glucose levels in people with____

-uses______ methods to automatically and frequently measure glucose levels in the ______of dermis or subcutaneous fat tissue.

A

diabetes

electrochemical
interstitial fluid

56
Q

Laboratory Test for Glucose (7)

A

1.Random plasma glucose
2.Fasting plasma glucose
3. Tolerance test
4. HbA1c
5. Fructosamine
6. Urine Microalbumin
7. Ketone testing

57
Q

LABORATORY TESTS

  • specimens collected anytime of the day
  • usually done in a glucometer
  • NO NORMAL VALUES
A

Random Plasma Glucose

58
Q

Random plasma glucose

Formerly known as

A

random blood sugar (RBS)

59
Q

Random Plasma Glucose

  • specimens collected_____
  • usually done in a_____
  • normal values?
A

anytime of the day

glucometer

NO NORMAL VALUES

60
Q

Principles:

Electrochemistry (Amperometry)

Glucose oxidase

A

Random plasma glucose

61
Q

LABORATORY TESTS

  • specimens collected after 8-10 hours fasting (new guideline)
    >7.0 mmol/L or >126 mg/dL (DM)
A

Fasting Plasma Glucose

62
Q

Fasting Plasma Glucose

  • formerly known as
A

fasting blood sugar (FBS)

63
Q

Fasting Plasma Glucose

  • specimens collected after ____hrs fasting (new guideline)

> ___ mmol/L or >___ mg/dL (DM)

A

8-10 hours

> 7.0 mmol/L or >126 mg/dL (DM)

64
Q

LABORATORY TESTS

  1. Fasting sample + urine
  2. 75 grams glucose load is orally taken within 15 minutes
  3. 1-hr sample + urine
  4. 2-hr sample + urine
A

Oral Glucose Tolerance
Test

65
Q

LABORATORY TESTS
Glucose Tolerance Test

-Diagnosis of GDM
• Fasting: >___ mmol/L (>___ mg/dL)
• 1 h: >___ mmol/L (>___ mg/dL)
• 2 h: >___ mg/dL (>___ mmol/L)

A

• Fasting: >5.1 mmol/L (>92 mg/dL)
• 1 h: >10.0 mmol/L (>180 mg/dL)
• 2 h: >153 mg/dL (>8.5 mmol/L)

66
Q

LABORATORY TESTS

-H6A1c
“Hemoglobin A that is irreversibly glycosylated at one or both N-terminal valines of the B-chains of the tetrameric hemoglobin molecule”

(International Federation of Chemistry Working Group on HBA1c)

A

Glycated/Glycosylated Hemoglobin

67
Q

Now the preferred test to assess glycemic control

Widely used marker of chronic hyperglycemia (reflecting average blood glucose levels over a 2-to 3-month period of time)

A

Glycated/Glycosylated Hemoglobin

68
Q

Glycated/Glycosylated Hemoglobin

Now the preferred test to assess_____ control

Widely used marker of_____ (reflecting average blood glucose levels over a 2-to 3-month period of time)

A

glycemic control

chronic hyperglycemia

69
Q

LABORATORY TESTS

Glycated/Glycosylated Hemoglobin
-METHODS: 5

A

• Affinity Chromatography
• HPLC
• Electrophoresis
• Spectrophotometry
• 2-step Non-enzymatic Method

70
Q

Specimen requirement for HBA1c is????

A

Whole blood

71
Q

HBAc1

Anticoagulant of choice:

A

EDTA

72
Q

LABORATORY TESTS

• Most widely used to assess short-term (3-6 week) glycemic control

• Most useful if the HBA1c is unreliable due to hemoglobinopathy or hemolysis

• Not ideal: serum albumin level is < 3 g/dL or when serum albumin turnover is accelerated (cirrhosis)

A

Fructosamine

73
Q

Fructosamine
• Most widely used to assess short-term (3-6 week)_____

• Most useful if the HBA1c is_____ due to_____ or ____

• Not ideal:_______ level is < 3 g/dL or when ______ turnover is accelerated (cirrhosis)

A

glycemic control

unreliable/ hemoglobinopathy or hemolysis

serum albumin

74
Q

LABORATORY TESTS

• test to detect very small levels of protein (albumin) in urine

  • To detect early diabetic nephropathy (kidney damage)
A

Urine Microalbumin

75
Q

Urine Microalbumin

• test to detect very small levels of____ in urine
- To detect early_____

A

protein (albumin)

diabetic nephropathy (kidney damage)

76
Q

LABORATORY TESTS

• Beta-HBA, acetoacetic acid, and
acetone
• To detect ketosis in DM type???

A

Ketone Testing

DM T1

77
Q

Ketone testing methods (4)

A

• METHODS:
- Electrochemistry
- chromatography
- Electrophoresis
- Colorimetric methods

78
Q

Ketone Testing
• METHODS:

• use of ferric chloride reacted with acetoacetic acid to produce a red color

A

Gerhardt’s

79
Q

Ketone Testing
• METHODS:

• reacts with acetoacetic acid in an alkaline pH to form a purple color
• urine reagent strip test and Acetest tablets

A

Sodium Nitroprusside

80
Q

Ketone Testing
• METHODS:

• to detect either 3-b-hydroxybutvric acid or acetoacetic acid

A

3-hydroxybutyrate dehydrogenase

81
Q

LABORATORY TESTS

2 hours following regular meal

A

2-Hour Postprandial Glucose

82
Q

LABORATORY TESTS

-75 grams glucose load
- Blood collection after 2 hours
• 200 mg/dL - DM

A

2-Hour Postprandial Glucose (more standardized)

83
Q

DIAGNOSTIC CRITERIA FOR DIABETES MELLITUS
• Random Plasma Glucose

A

> 200 mg/dL (11.1 mmol/L)

84
Q

DIAGNOSTIC CRITERIA FOR DIABETES MELLITUS

Fasting Plasma Glucose

A

> 126 mg/dL (7.0 mmol/L)

85
Q

DIAGNOSTIC CRITERIA FOR DIABETES MELLITUS

2-hour Plasma Glucose OGTT

A

> 200 mg/dL (11.1 mmol/L)

86
Q

DIAGNOSTIC CRITERIA FOR DIABETES MELLITUS

Н6А1с

A

> 6.5%