CARBOHYDRATE: LABORATORY APPLICATIONS Flashcards
1
Q
11% lower than serum or plasma
A
Whole blood
2
Q
reduction of cupric ions to cuprous ions forming
cuprous oxide in hot alkaline solution by glucose
A
Alkaline Copper Reduction Method
3
Q
____________can be separated within 30 minutes
A
Serum
4
Q
Most of the laboratory hospitals are using _____ and __________ in
glucose determination
A
plasma and serum
5
Q
___________are not accepted in the lab because it is
mandated under the code of ethics to release accurate and
precise results in accordance with the quality assurance and
quality control in the laboratory
A
hemolyzed
6
Q
________is present in the gray tube which is used for
glucose determination
A
sodium flouride
7
Q
- Sodium fluoride inhibits the glycolytic enzyme called the __________ which acts as an anticoagulant
A
Enolase
8
Q
__________ decreases serum glucose by approximately _________hour __________ in normal uncentrifuged coagulated
blood at room temperature
A
Glycolysis - 5% - 7% in 1 hour (5 to 10 mg/L)
9
Q
In separated, non-hemolyzed sterile serum, stable as long as ____________
A
8 hours at 25°C and up to 72 hours at 4°C.
10
Q
Serum w/o bacterial contamination and without leukocytosis
(increased WBCs) =
A
up to 90 minutes delay
11
Q
Give me the possible samples
A
Whole blood
Plasma
Serum
Cerebrospinal fluid
Pleural Fluid
Urine
12
Q
stable up to 48 hrs
A
- Serum or Plasma:
13
Q
2mg Na fluoride per mL of whole blood (48 hrs)
A
Whole blood
14
Q
There are 2 glucose methodologies
A
- Chemical method
- Enzymatic method
15
Q
๏We do not accept unhemolyzed venous plasma/serum
A
Serum
16
Q
give me the four alkaline copper reduction method
A
- Folin Wu Method
- Nelson’s Somogyis method
- Neocuproine method
- Benedicts method
17
Q
Alkaline ferric reduction method
A
a. Hagedom method
B. Condesation method
a. Dubowski method
18
Q
give me the formula of oxidation reduction method
A
k
19
Q
The glucose reduces cupric ions present in the alkaline
copper reagent to cuprous ions or the cupric sulfate is
converted to cuprous oxide which reduces the
phosphomolybdic acid to phosphomolybdous acid
A
a. Folin Wu Method
20
Q
Give me the formula of folin wu method
A
k
21
Q
folin wu method color
A
BLUE
22
Q
● Sugars with reducing properties are rising out
of the presence of the potential aldehyde or
keto group called
A
reducing sugars
23
Q
Example of reducing sugar
A
Glucose, Galactose, Lactose, Maltose
24
Q
One of the classical and widely used methods for the
quantitative determination of the reducing sugars
A
Nelson Somogyi Method
25
* The reducing sugars when heated with the alkaline copper
tartrate reduce copper from the cupric state and cuprous
oxide is formed
Nelson somogyi method
26
When cuprous oxide is heated with arsenomolybdate, there
will be reduction of _________ which has
the color blue
molybdic acid to molybdenum
27
(2,9 Dimethyl 1,10 Phenanthroline Hydrochloride)]\
Neucoproine Method
28
The copper in oxidation state reacts with neocuproine
forming a ____________
Complex - neuocuproine method
29
this complex is extracted into a
________________ giving a yellow or yellow-orange solution
chloroform methanol mixture
30
* Used for detection and quantitation of reducing substances
in body fluids like blood and urine
Benedicts method
31
* Used citrate or tartrate as stabilizing agent
Benedict's Method
32
* Used to test for simple carbohydrates
Benedict's Method
33
Colometric
Dye
34
* Identifies reducing sugars (ex. Monosaccharides and some
disaccharides which have 3 ketone or aldehyde functional
groups)
Benedicts method
35
* Can be used for identification of glucose in the urine
Benedicts Method
36
* It has a principle that when the reducing sugars are mixed
with the Benedict’s reagent and heated, a reduction
reaction causes the benedict’s reagent to _________
Change color
37
* Color varies from ___________, rusty brown =
depending on the amount of sugar
green to brick red
38
___________are easily oxidized to yield
carboxylic acid
* Fehling’s Test - aldolases
39
____________ is reduced to
cuprous oxide forming the product of brick red color
* Cupric ion complex with tartrate ion
40
Reducing _________ and ________are chemical
compounds that can be oxidized by reducing other
sugars and aldehydes
41
* Benedict’s solution contains the ___________
Cu 2+ citrate
42
Fehling’s solution contains the _____________
Cu 2+ tartrate
43
* It involves reduction of yellow ferricyanide to a colorless
ferrocyanide by glucose (inverse colorimetry)
Alkaline Ferric Reduction Method (Hagedorn Jensen)
44
Condensation of glucose with primary aromatic amine in
glacial acetic acid, forming an equilibrium mixture of a
glycosylamine and the corresponding Schiff base
* Ortho-toluidine (Dubowski Method)
45
Glucose in a PFF (3% TCA) reacts to OToluidine in hot acidic solution will yield a GREEN colored
compound with maximum absorbance at 630 nm
Dubowski method
46
Dubowski method color is ________
Green
47
Acts on glucose but not on other sugars and reducing
substances
ENZYMATIC METHODS
48
______________ is the most specific enzyme reacting only with
B-D-glucose
Glucose oxidase method
49
_____________converts B-D-glucose gluconic acid and the
oxygen is consumed and H2O2 is being produced
Glucose oxidase method
50
colorimetric glucose oxidase method AKA
Saifer Gerstenfield method
51
is used to catalyze the second reaction.
● Horseradish peroxidase
52
Shift in the absorbance can be monitored
spectrophotometrically and its proportional to the
amount present in the specimen
This couple reaction is known as the ____________
trinder reaction.
53
Peroxidase couple reaction used glucose oxidase
method is subject to _______________
+ and - interference
54
Strong oxidizing substances, such as ___________, can cause falsely increased values
bleach
55
Increased levels of ___________
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.
uric acid, bilirubin, and ascorbic acid
56
In benedicts test blue color is
None
57
is used to oxidize a dye compound to commonly
chromogens are used in this type of method
● H2O2
58
Measures rate of oxygen consumption which is proportional to
glucose concentration
Polarographic Glucose Oxidase
59
in the absorbance can be monitored
spectrophotometrically and its proportional to the amount
present in the specimen
shift - CGOM
60
Glucose oxidase in the reagent catalyzes the oxidation of
glucose by oxygen under first order conditions, forming
hydrogen peroxide
61
___________ by the consumption of oxygen on an oxygensensing electrode (CGOM
Quantitated
62
____________ is prevented from re-forming oxygen by
adding molybdate, iodide, catalase and ethanol
Hydrogen peroxide
63
Oxygen consumption can be used to perform the direct
measurement of oxygen by ___________
polarographic technique.
64
Must be eliminated in the side reaction to prevent the
reaction from reversing.
* H2O2
65
Traces of reducing sugar
Green/yellow ppt
66
More accurate than glucose oxidase method
HEXOKINASE METHODS
67
MOST SPECIFIC GLUCOSE METHOD; REFERENCE
METHOD
Hexokinase methods
68
Less interference
Hexokinase methods
69
Other samples; UCS
Hexokinase method
70
Plasma collected using heparin, EDTA, flouride, oxalate or
citrate may be used for this test
Hexokinase method
71
in the presence of ATP converts glucose to glucose
6 phosphate
hexokinase method
72
● glucose 6 phosphate and cofactor NADP are converted
into 6 phosphogluconate at ______ maximum absorbance
measuring the rate of appearance of NADPH and
NADPH by glucose 6 phosphate dehydrogenase.
340
73
_________may cause a
false decrease in results. (Hexokinase method)
Gross hemolysis and extremely elevated bilirubin
74
is reduced to produce a chromophore that is measured
spectrophotometrically or an electrical current
Glucose
75
___________ is added to shorten the time
Mutarotase
76
_____________is touched to a drop of blood and inserted into the
meter which gives a digital reading of the blood sugar; gives the
unit of mmol/L
Dextrostics (cellular strip
77
An enzyme-impregnated strip used with a small portable
electronic colour-measuring device for convenient estimation of
the blood sugar levels by diabetics
Dextrostics (cellular strip)
78
The whole blood capillary glucose values obtained with
POC devices are useful for the detection of ________ and __________ in individuals with
diabetes
hypoglycemia and hyperglycemia
79
* It should not be used to diagnose diabetes or hypoglycemic
disorders
Dextrostics (cellular strips)
80
used for continuous monitoring of glucose levels in people with
diabetes
Interstitial Glucose Measuring Device
81
uses electrochemical methods to automatically and frequently
measure glucose levels in the interstitial fluid of dermis or
subcutaneous fat tissue
Interstitial Glucose Measuring Device
82
* Result of this test provides an idea of the glucose patterns over
hours or days
Interstitial Glucose Measuring Device
83
Formerly random blood sugar (RBS)
RANDOM PLASMA GLUCOSE
84
* Specimens collected anytime of the day
RANDOM PLASMA GLUCOSE
85
* Usually done in a glucometer
RANDOM PLASMA GLUCOSE
86
* NO NORMAL VALUES in RPG
* Bcs the glucose is measured randomly
87
Electrochemistry (Amperometry)
Principle of glucometer
88
● Gluosse oxidase
Principle of glucometer
89
● Works with the sensors or amperometry
Principle of glucometer
90
● First step to measure the glucose in the blood is to convert
glucose concentration into voltage or amount or the current
signal
RANDOM PLASMA GLUCOSE
91
● This is possible with the special sensor strip for amperometry
RANDOM PLASMA GLUCOSE
92
● The sensor uses the ______________ to form part
of the electric circuit where hydrogen peroxide is electrolyzed
platinum or the silver electrode
93
● The hydrogen peroxide is produced as a result of the oxidation
of glucose on the glucose oxide membrane and the current
flowing through the circuit provides the measurement of the
concentration of hydrogen peroxide hence giving the
concentration of glucose
RANDOM PLASMA GLUCOSE
94
* Formerly fasting blood sugar (FBS)
FASTING PLASMA GLUCOSE
95
* Specimens collected after 80-10hrs fasting (new
* guideline)
FASTING PLASMA GLUCOSE
96
* Nothing by mouth
FASTING PLASMA GLUCOSE
97
Sometimes accept patients that have drank small amount
of water; physician must be informed
FASTING PLASMA GLUCOSE
98
* >7.0mml/L or > 126mg/gL diabetes mellitus (DM)
FASTING PLASMA GLUCOSE
99
To determine how well your body metabolizes glucose over
a required period of time
* Oral Glucose Tolerance Test
100
* 3 samples in total
* Oral Glucose Tolerance Test
101
Test for pregnant women and older
Oral glucose tolerance test
102
is irreversibly glycosylated at one or both Nterminal valines of the B-chains of the tetrameric
hemoglobin molecule (International Federation of
Chemistry Working Group on HBA1c
Hemoglobin A
103
Is the largest subfraction of normal HBA involved in diabetic
and nondiabetic individuals
HbA1c
104
Represents the weighted average of glucose levels with the
youngest erythrocytes contributing to a greater extent than
the older ones
HbA1C
105
Glucose tolerance test in 1 hour
: >10.0 mmol/L (>180mg/dL)
106
Glucose tolerance test in 2 hours
>153 mg/dL (>8.5 mmol/L
107
fasting in GTT
>5.1 mmol/L (>92 mg/dL)
108
* Now the preferred test to assess glycemic control
GOT
109
RBC lifespan
120 days - 3-4 months
