Lipid & Lipoprotein Measurement

Question 1

Enumerate the biological variations that can affect lipid and lipoprotein levels

Answer 1

Age
Sex
Seasonal
Dietary intake
Medications
Medical disorders
Lifestyle and other biological variation

Question 2

The higher the age, the ____.

Answer 2

higher the cholesterol

Question 3

Women have ___ cholesterol levels than men.

Answer 3

lower

Question 4

Cholesterol levels are ___ in the winter.

Answer 4

slightly higher

Question 5

A person should be on their usual diet for __ weeks.

Answer 5

2

Question 6

Daily intake of fat will ___ cholesterol level.

Answer 6

increase

Question 7

In terms of acute illnesses, lipoprotein measurement should be made no sooner than ____ after any form of trauma or acute bacterial/viral infection, and ____ after childbirth.

Answer 7

8 weeks
3-4 months

Question 8

True or false: Total cholesterol, HDL, LDL, and TAG can be measured in fasting patients only.

Answer 8

False

Question 9

These can be measured in non-fasting individuals.

Answer 9

Total cholesterol
High-density lipoprotein

Question 10

Requires fasting individuals

Answer 10

Triglycerides
Low-density lipoprotein

Question 11

The ideal time that patients should fast before venipuncture

Answer 11

12 hours

Question 12

Chylomicrons can markedly ___ the plasma triglyceride concentration.

Answer 12

increase

Question 13

Chylomicrons are almost completely cleared within how many hours?

Answer 13

6-9 hours

Question 14

The presence of chylomicrons after a ___ hour fast is considered ___.

Answer 14

12-hour
abnormal

Question 15

What does NCEP mean?

Answer 15

National Cholesterol Education Program

Question 16

Some LPP physiologically __ after meals due to __ changes.

Answer 16

decline/decrease
CETP-mediated compositional changes (Cholesteryl ester transfer protein)

Question 17

When do CETP-mediated compositional changes occur?

Answer 17

When chylomicrons are catabolized

Question 18

The NCEP Adult Treatment Panel III (ATP III) has recommended that patients fast for at least ___ before blood specimens are taken for lipid and lipoprotein analysis.

Answer 18

9 hours

Question 19

When a standing patient reclines, concentrations of __, ___, and ___ decrease as much as ___.

Answer 19

Total cholesterol, Low-density lipoprotein, High-density lipoprotein
10%

Question 20

Position of the patient must be standardized for venipuncture, preferably to the ___.

Answer 20

sitting position

Question 21

When a standing patient reclines, ___ transfers to the ___ and dilutes non-diffusible plasma constituents.

Answer 21

extravascular water
vascular system

Question 22

The NCEP guidelines recommend that patients be seated for ___ before sampling to prevent ___.

Answer 22

5 minutes
hemoconcentration

Question 23

Hemoconcentration increase cholesterol by ___.

Answer 23

10-15%

Question 24

Prolonged venous occlusion can lead to ___ and cholesterol increases ____.

Answer 24

hemoconcentration
10-15%

Question 25

Plasma is preferred when the lipoproteins are measured by ___ and ___.

Answer 25

ultracentrifugation electrophoresis

Question 26

Why is plasma preferred?

Answer 26

Samples can be cooled to 4°C and retire the changes occurring at room temperature.

Question 27

True or false: Plasma should remain in contact with the cells overnight.

Answer 27

False (should not)

Question 28

___ occurs less frequently using serum

Answer 28

Protein aggregation

Question 29

True or false: Protein aggregation can still occur in plasma, even in the presence of an anticoagulant.

Answer 29

True

Question 30

What anticoagulant does a blue top tube contain?

Answer 30

Citrate

Question 31

What anticoagulant does a green top tube contain?

Answer 31

Heparin

Question 32

What anticoagulant does a purple top tube contain?

Answer 32

Ethylenediamine-tetraacetic acid (EDTA)

Question 33

___ exert rather large osmotic effects that result in ___ plasma lipid and lipoprotein concentrations.

Answer 33

Citrate falsely low

Question 34

_____, because of its relatively high molecular weight, has little effect on plasma volume but can alter the electrophoretic mobilities of the lipoproteins.

Answer 34

Heparin

Question 35

What is the preferred anticoagulant?

Answer 35

EDTA

Question 36

True or false: Ethylenediaminetetraacetic acid (EDTA) is the preferred anticoagulant even though cholesterol and triglyceride concentrations in EDTA plasma are about 5% lower than in serum.

Answer 36

False (3%)

Question 37

EDTA retards certain kinds of ___ and ___ occurring in your lipoprotein during storage.

Answer 37

oxidative enzymatic alterations

Question 38

These can be analyzed with frozen samples

Answer 38

Total protein, Triglycerides, High-density lipoprotein, Apolipoproteins

Question 39

What are the storage requirements for a sample?

Answer 39

Long-term (>2 months): −70°C or lower Short-term (1-2 months): −20°C

Question 40

Why are frozen samples not appropriate for ultracentrifugal analysis?

Answer 40

Triglyceride-rich lipoprotein does not withstand freezing

Question 41

What are the most common chemical methods for your cholesterol?

Answer 41

Liebermann-Burchard Test Salkowski Test Abell-Kendall Test

Question 42

Two laboratory methods (cholesterol)

Answer 42

Chemical methods Enzymatic methods

Question 43

Positive indicator of Liebermann-Burchard's test

Answer 43

Green

Question 44

In Liebermann-Burchard's test, the dry extract was dissolved in ___ then ___ was added along the sides of the test tube.

Answer 44

acetic anhydride concentrated sulfuric acid

Question 45

Positive indicator of Salkowski's reaction

Answer 45

Red

Question 46

A positive result in Liebermann-Burchard's test indicates what?

Answer 46

presence of steroids

Question 47

A positive result in Salkowski's reaction indicates what?

Answer 47

presence of steroids

Question 48

In Salkowski's reaction, the dry extract was shaken with ___, forming ___, then ___ was added slowly by the sides of the test tube.

Answer 48

chloroform chloroform layer sulfuric acid

Question 49

In the Abell-Kendall method, ___ are hydrolyzed with ___ to unesterified form.

Answer 49

cholesteryl esters alcoholic potassium hydroxide (KOH)

Question 50

In the Abell-Kendall method, unesterified cholesterol is extracted with ___ and measured with the ___.

Answer 50

petroleum ether Liebermann-Burchard reagent

Question 51

The Liebermann-Burchard reagent is composed of?

Answer 51

Sulfuric acid Acetic acid Acetic anhydride

Question 52

Positive indicator of the Abell-Kendall method

Answer 52

Bluish-green

Question 53

The enzymatic method will use a ___ sample volume.

Answer 53

smaller

Question 54

It is rapid and precise compared to the other method.

Answer 54

enzymatic method

Question 55

Cholesteryl ester with the combination of water will be acted by the ___ forming ___ and ___.

Answer 55

cholesteryl esterase cholesterol; free fatty acid

Question 56

Cholesterol, with the action of added oxygen, will be acted by the ___ forming ___ and ___.

Answer 56

cholesterol oxidase cholest-4-en-3-one; hydrogen peroxide

Question 57

Hydrogen peroxide, one of the reaction products, is measured by ___ that will now form a colored dye which is the ___.

Answer 57

peroxidase-catalyzed reaction Quinoneimine

Question 58

What device is used to quantitate the cholesterol level?

Answer 58

Spectrophotometer

Question 59

What are the interfering substances that react in the chemical methods?

Answer 59

plant sterol ascorbic acid bilirubin sample turbidity high levels of hemoglobin

Question 60

Ascorbic acid interferes by consuming what?

Answer 60

hydrogen peroxide

Question 61

High levels of ascorbic acid or bilirubin level lead to a ___ of the result.

Answer 61

false decrease

Question 62

The hydrogen peroxide produced in the cholesterol oxidase reaction can be oxidatively coupled to two chromogenic substrates by catalysis with a peroxidase, most commonly ___.

Answer 62

horseradish peroxidase

Question 63

Chromogens

Answer 63

phenol 4-aminoantipyrine

Question 64

The quinoneimine dye can be read photometrically at?

Answer 64

500nm

Question 65

True or false: Enzymatic methods require a preliminary extraction step.

Answer 65

False (NO preliminary extraction step)

Question 66

One chemical method still used is the ___.

Answer 66

CDC reference method for triglycerides

Question 67

The CDC-reference method uses a ___ extraction (of triglycerides) procedure followed by ___ to isolate ___.

Answer 67

chloroform silicic acid chromatography

Question 68

Glycerol is released by ___.

Answer 68

Saponification

Question 69

Positive indicator of the CDC-reference method

Answer 69

Pink

Question 70

This limits interfering substances.

Answer 70

CDC-reference method

Question 71

NADH formation can be measured spectrophotometrically at __.

Answer 71

340nm

Question 72

The disappearance of NADH is measured at ___.

Answer 72

340 nm

Question 73

This is separated by chemical precipitation.

Answer 73

HDL Cholesterol

Question 74

What are the precipitating agents used in HDL-cholesterol measurement?

Answer 74

Earliest – heparin in combination with manganese to precipitate apo B-containing LPP (lipoprotein) Alternative – sodium phosphotungstate with magnesium More specific – Dextran sulfate with magnesium

Question 75

Interfering factor (HDL-Cholesterol measurement)

Answer 75

elevated triglyceride levels

Question 76

What is/are the gold standard/reference method in HDL-Cholesterol measurement?

Answer 76

Ultracentrifugation – to remove VLDL Heparin Manganese Precipitation – to remove LDL Analysis of supernatant cholesterol by the Abell-Kendall Assay

Question 77

What is/are the reference method for LDL-cholesterol measurement?

Answer 77

Beta-Quantification Electrophoretic migration Ultracentrifugation + Chemical precipitation

Question 78

LDL-Cholesterol Method routine method

Answer 78

Friedewald Calculation

Question 79

Reference range for Total Cholesterol

Answer 79

140-200 mg/dL (3.6-5.2 mmol/L)

Question 80

Reference range for high-density lipoprotein cholesterol

Answer 80

40-75 mg/dL (1.0-2.0 mmol/L)

Question 81

Reference range for low-density lipoprotein cholesterol

Answer 81

50-130 mg/dL (1.3-3.4 mmol/L)

Question 82

Reference range for triglycerides

Answer 82

60-150 mg/dL (0.7-1.7 mmol/L)

Question 83

What is the equation of Friedewald?

Answer 83

LDL = TC - HDL - (TAG/2.175) (mmol/L) LDL = TC - HDL - (TAG/5) (mg/dL)