Carbohydrates Flashcards
(19 cards)
Ideal fasting for lipid measurement
12-14 hour
Chylomicrons are completely cleared within — hours
6-9 hours. Presence after 12hrs is abnormal
These lipids may not need fasting
TC and HDL
These lipids SHOULD be fasting specimen
TAG and LDL
Standing to recline position effect on lipids
10% increase in TC, LDL, HDL, apoA1, apoB
50% decrease in TAG
Prolonged tourniquet effect on lipid
Increase 10-15% of chol
What specimen is used for ultracentrifugation and electrophoresis
EDTA plasma
Because samples can be cooled to 4C that stops changes at RT
Why is citrate not used for lipid measurement
Osmotic effects that result to low plasma lipid and LPP concentration
When plasma is used for lipid ms, how long should it be separated
Within 3 hours
To avoid RBCs using the lipids
Advantage of using serum over plasma in lipid
Lesser protein aggregation, and can be stored longer
What lipids can be tested with frozen sample in electrophoresis
Chol, TAG, HDL, apoproteins
T or F: frozen samples can be used for ultracentrifugation
False
In frozen samples, what lipid ms can be acquired through calculation
LDL by Friedewald equation
What are the general steps in ms TAG
Extraction
Hydrolysis (saponification)
Measurement of liberated glycerol
Extraction of TAG in non-enzymatic method is done using
Methanol
Ethanol
Isopropanol
Chloroform-ethanol (Folch’s reagent)
Diethyl ether
This step is the hydrolysis of TAG to yield fatty acid and glycerol
Saponification
What is used in saponification step in TAG ms
Alcoholic KOH (at elevated temp)
KOH-hydrolysis
Ethanol- allows material to remain in soln
Elevated temp- enhance rate of hydrolysis
In TAG ms what reactions are used to quantify formaldehyde
Eegrine’s reaction- 565nm
Schryver’s reaction- 540nm
Pay’s reaction- 620nm
Hantzsch reaction- 410nm
T or F: extraction step is eliminated in TAG enzymatic method
True
