Measurement of Lipids and Lipoproteins
CCHM 321- Final Period
Prepared by: Billy Africa, RMT, MPH
Learning Objectives:
• At the end of the session, the students are expected to be
able to:
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•
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Rationalize the requirements regarding patient preparations;
specimen collection; transport processing and handling
Discuss the principle involved, advantages and disadvantages of
laboratory methods of lipid & lipoproteins
Enumerate the reference value of each lipid measured
Correlate laboratory results with patients lipid or lipoprotein status
Relate the laboratory data in the assessment of risk or coronary heart
disease
Discuss the significance played by cardiac proteins and enzymes in
the diagnosis of heart diseases
LABORATORY TEST FOR LIPOPROTEIN AND LIPID
DISORDER
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•
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The patient should remain on a regular
diet for at least ____________ prior to
the blood sample being taken.
No consumption of alcohol for at least
____________
The sample must be collected after a
fast of at least ___________.
DETERMINATION OF Total Cholesterol
(Free- 1/3, Esterified – 2/3)
•
ENZYMATIC METHOD
– Faster to perform
– Use less ___________ chemicals
– To diminish the problems associated with
esters and ____________
– Hydrolysis of cholesterol esters and
oxidation of __________
PRINCIPLE
• Hydrolysis;
– Cholesterol esters - cholesterol esterase – cholesterol + fatty
acics
• Oxidation:
– Cholesterol + O2 -cholesterol oxidase – cholest-4-ene-3-one +
H2O2
– 2 H2O2 + 4-aminophenazone – peroxidase – quinoneimine dye
• Measure absorbance at ____________
Reference Values:
• 125 mg/dL (__________mmol/L)
• Women<men but after menopause W>M
Conversion: mg/dL to mmol/L (_______)
CHEMICAL METHODS
•
Liebermann-Burchardt (L-B) Procedure
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one step direct method
cholesterol + H2SO4 + acetic anhydride = ___________
measure at _________
Other serum constituents such as ________ and
___________ absorb strongly in this region and may produce
falsely elevated values.
Abell-Kendall Method
• Precipitation of cholesterol esters after _________
separate esterified from free cholesterol, permitting
measurement of only the__________
• Extraction: specimen + zeolite = __________
– Cholesterol esters – hydrolysis – free cholesterol
DETERMINATION OF HDL CHOLESTEROL
• Precipitation of VLDL and LDL by the addition of reagent
containing:
➢ heparin-MgCl2;
➢ dextran sulfate-MgCl2 and
➢ ___________________
• Centrifugation – HDL is the only ________ remaining in the
supernate
• Determination of cholesterol by ____________
DETERMINATION OF HDL CHOLESTEROL
• Apolipoprotein of HDL (Apo AI and AII) Apolipoprotein B of
_______ can be measured by:
– Enzyme Linked Immunoassay (ELISA)
– Immunonephlelometry (INA)
DETERMINATION OF LDL CHOLESTEROL
• Difficult to measure directly, but it may be calculated from
the measurement of total and HDL cholesterol and
____________ in plasma
DETERMINATION OF LDL CHOLESTEROL
•
LDL cholesterol = Total cholesterol – (HDL + VLDL)
•
When concentration of triglycerides (TG) is less than
________ mg/dL, the usual ration of VLDL:TG = 1:5
hence VLDL cholesterol = TG/5
•
LDL Cholesterol = Total Cholesterol – (HDL + TG/5)
DESIRABLE VALUES FOR LDL and HDL
CHOLESTEROL
• >2.0 mmol/L or >_____mg/dL for HDL
• <3.4 mmol/L or <_____mg/dL for LDL
• LDL: HDL - <3:__ is considered desirable
DETERMINATION OF PLASMA
TRIGLYCERIDES
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Hydrolysis of triglyceride to form glycerol and
_________
Measurement of glycerol present (either as ________ or
after conversion to another product)
Measure spectrophotometrically, fluorometrically or
____________
Reference Values
• < 250 mg/dL or ______ mmol/L – mild elevation
• 250-500 mg/dL or _______ mmol/L – possible markers for
genetic form og hyperlipoproteinemia
• > 500 mg/dL or > ______ mmol/L – should be treated
vigorously, increase risk for _________
Lipoprotein phenotypes
(Friedrickson classification)
Phenotype
I
Lipoprotein Elevated
Major plasma lipid
elevated
Chylomicrons
TAG
IIa
LDL
Chole
IIb
LDL and VLDL
Chole and TAG
III
B-VLDL, IDL, CM remnants
Chole and TAG
IV
VLDL
TAG
V
VLDL and CM
Chole and TAG
Dyslipoproteinemia
Hyperlipoproteinemia
• Hyperchylomicronemia –________________
– Familial lipoprotein lipase deficiency
– Familial Apo C deficiency
• Familial hypercholesterolemia – ________________
– presence of ___________ (cholesterol deposits in tissues
under the skin)
Hyperlipoproteinemia
• Familial dysbetalipoproteinemia –
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• Familial Hypertriglyceridemia –
• Type V Hypertriglyceridemia –
Hyperlipoproteinemia
• Familial combined hyperlipidemia – elevation of VLDL and
LDL or both
• Hyper-α-lipoproteinemia – increased HDL
Hypolipoproteinemia
• Abetalipoproteinemia –______________________
• Familial-β-lipoprotein deficiency – _____________
• Familial hypo-α-lipoproteinemia – ______________
Lipidoses
Lipidoses
Deficiency
Accumulated Materials
Krabbe’s disease
β-D-Galactosidase
Galactocerebrosides
Fabry’s disease
α-D-Galactosidase
_____________
Tay-Sach’s disease
_________________
Ganglioside GM2
Metachromatic
Leukodystrophy
Sulfatide Sulfatase
________________
Niemann-Pick disease
_________________
Sphingomyelin
Gaucher’s disease
β-D-Glucosidase
_____________
Diseases Associated with
Abnormal Lipid Concentration
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Arteriosclerosis
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Hyperlipoproteinemias
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Hypercholesterolemia
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Hypertriglceridemia
Diseases Associated with Abnormal
Lipid Concentration
•
Combined Hyperlipoproteinemias
•
Lp(a) elevation
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Hypolipoproteinemia
•
Hypoalphalipoproteinemia
• Reference:
– Bishop, Michale L, Clinical Chemistry, 8th Edition