Lipid profile Flashcards
What are the characteristics of atherosclerosis?
Disease in which plaque builds up inside the arteries, causing them to narrow
Disrupts blood flow
Eventually reduces the supply of oxygenated blood to affected regions of the body
What are atherosclerotic plaques made up of?
Fat
Cholesterol
Calcium
ECM proteins like collagen
Cells
Which cells make up atherosclerotic plaques?
Smooth muscle cells
Macrophages
Foam cells
What are the risk factors of atherosclerosis?
High fat diet
Lack of exercise
Obesity
Excessive alcohol consumption
Smoking
High blood pressure
Diabetes
Family history
Ethnicity
What conditions are caused by atherosclerosis?
Angina
Stroke
Claudication
MI
What are the two forms in which lipids can be found in the body?
Triglycerides
Cholesterol
Characteristics of triglycerides
Esters derived from glycerol and three fatty acids
Fatty acid moieties can be saturated or unsaturated
The combination of 3 fatty acids and glycerol backbone = triglycerides
Characteristics of cholesterol
Carried in the blood by proteins
When combined = lipoproteins
What are the two major forms of cholesterol in the body?
LDLs - carry cholesterol from the liver to the cells of the body
HDLs - carries cholesterol away from cells back to the liver where it is broken down or passed out of the body as waste products
What is an ester?
Organic compound
Made by replacing the hydrogen of an acid by an alkyl or other organic group
Many naturally occurring fats and essential oils are esters of fatty acids
What is a sterol?
Cholesterol is a sterol
Modified steroid molecule
What is an important function of cholesterol?
Essential component of cell membrane
What is the function of lipid profiles?
Help assess the risk of an unhealthy person to have high cholesterol/ triglycerides
What sample is taken to undertake a lipid profile?
Blood taken after an overnight fast
Plasma - blood collected in a heparin or EDTA tube
Serum - blood collected in an SST (serum-separating tube)
What colour is an EDTA vacutainer?
Lilac
What colour is a heparin vacutainer?
Green
What colour is a serum vacutainer?
Gold
Which laboratory carries out lipid profiles?
Clinical biochemistry laboratories
What is a lipid profile?
Collection of several tests
- triglycerides
- total cholesterol
- HDL cholesterol
- LDL cholesterol
- total cholesterol/ HDL ratio
What type of assay is used to measure the components of the lipid profile?
Colourimetric assay
What is a colourimetric assay?
Add a reagent to cause colour change
Cholesterol is measured via oxidation with cholesterol esterase and cholesterol oxidase
Yields hydrogen peroxidase which reacts with a dye to produce a red-coloured solution
The optical density of the solution is measured using a spectrophotometer incorporated into the analyser
The optical density is proportional to the concentration of cholesterol
[cholesterol] is calculated using a calibrated standard curve
What do different modules on the automated analysers measure?
Different modules carry out different types of assay
Lipids, cardiac markers, tumour markers and hormones can all be measured using colourimetric assay on a single module
One module is capable of carrying out many different assays using the same basic colourimetric assay with different reagents
What do the results of colorimetric testing for cholesterol show?
The results are compared to a reference range
Reference ranges depend on whether they are deemed safe or concentrations that are lower in high risk concentration
Goal for those at high CVD risk is lower than minimum goal concentration in normal population
What is high triglyceride linked to?
Insulin resistance
Lack of fatty acid and triglyceride suppression
