lipid determination Flashcards
Conversion Factors:
Cholesterol to mmol/l
= 0.026
mg/dL mmol/L
Conversion Factors:
triglycerides to mmol/l
= 0.0113
mg/dL to mmol/L
conversion of cholesterol tommol/l
0.0259
The patient should remain on a regular diet for at least
_____ weeks prior to the blood sample being taken.
3 weeks
There should be no significant weight gain or loss. No consumption of alcohol for at least ___days
The sample must be collected after a fast of at least __.
12 hour
ATP III Classification for TAG Values
<150 mg/dL - normal
< 150 - 199 - borderline high
< 200 - 499 mg/dl - high
>500 mg/dl high
Increased triglyceride can be seen in
Hyperlipoproteinemia Type I, IIb, III and IV and V
Alcoholism
Nephrotic Syndrome
Hypothyroidism
Pancreatitis
Decreased triglyceride can be seen in
Malabsorption Syndrome
Hyperthyroidism
Malnutrition
Brain Infarction
determination of total cholesterol
Faster to perform
enzymatic method
determination of total cholesterol
Use less corrosive chemicals
ENZYMATIC METHOD
determination of total cholesterol
To diminish the problems associated with esters and other sterols
ENZYMATIC METHOD
determination of total cholesterol
Hydrolysis of cholesterol esters and oxidation of cholesterol
ENZYMATIC METHOD
reference values for total cholesterol
125 mg/dL (3.2 mmol/L)
conversion of cholesterol tommol/l
0.0259
comparison of cholesterol for sex
Women<men
but after menopause W>M
principle for total cholesterol
Hydrolysis; Cholesterol esters - cholesterol esterase – cholesterol + fatty acids
Oxidation: Cholesterol + O2 cholesterol oxidase – cholest-4-en-3-one + H2O2
2 H2O2 + 4-aminophenazone – peroxidase – quinoneimine dye
Measure absorbance at 500 nm
chemical methods for total cholesterol
one step direct method (simplest approach)
Liebermann-Burchard (L-B) Procedure
chemical methods for total cholesterol
End product – Cholestadienyl disulfonic acid (Red end color)
Salkowski Reaction
Three step method – saponification > extraction > colorimetry
Abell- Kendall Method
Precipitation of cholesterol esters after extractiuon separate esterified from free cholesterol, permitting measurement of only the free fraction
Abell- Kendall Method
Extraction: specimen + zeolite =
cholesterol
Cholesterol esters – hydrolysis – ______
free cholesterol
Methods for total cholesterol determination
Bloor’s method
1st step: extract using Bloor’s reagent
2nd step: Liebermann-Burchard
End color: Bluish green
Methods for total cholesterol determination
Abell-kendall method
1st step: Saponification
2nd step: extract using Zeolite
3rd Step: LB reaction
2 enzymes involved:
Cholesterol esterase – converts esterified cholesterol into free cholesterol
Cholesterol oxidase – oxidize into H2O2
CDC Reference Method for total cholesterol
Abell, Levy and Brodie Method
Current Reference Method for total cholesterol
GC MS
increase total cholesterol are can be seen in ___
Hyperlipoproteinemia Type II, III and IV
Biliary Cirrhosis
Alcoholism
Nephrotic Syndrome
Primary Hypothyroidism
DM – poorly controlled
decrease total cholesterol are can be seen in ___
Severe hepatocellular disease
Malabsorption Syndrome
Hyperthyroidism
Malnutrition
Severe Burns
Reference method for quantitation of lipoproteins
Ultracentrifugation
Electrophoresis
pattern:
HDL, VLDL, LDL, Chylomicrons
Stains for lipoproteins
: Oil Red O, Fat Red 7B, Sudan Black ester bonds in TAG and CE
are used for lipoprotein as it is sensitive and beneficial for the differentiation of lipoprotein
Agarose Gel
Chromatographic Methods for lipoprotein
Gel chromatography or Affinity Chromatography
The concentration of HDL cholesterol appears to be inversely related to the risk of ___
CVD
Centrifugation – __ is the only LP remaining in the supernate
HDL
DESIRABLE VALUES FOR
LDL and HDL CHOLESTEROL
> 2.0 mmol/L or >45 mg/dL for HDL
<3.4 mmol/L or <130 mg/dL for LDL
LDL: HDL - <3:1 is
considered desirable
