The lipid profile is a group of tests that are often ordered together to
determine risk of coronary heart
disease. The tests that make up a lipid
profile are tests that have been shown to be good indicators of whether
someone is likely to have a heart attack
or stroke
caused by blockage of blood vessels (hardening of the arteries).
What tests are included in a lipid
profile?
The lipid profile includes
total cholesterol,
HDL-cholesterol (often
called good cholesterol), LDL-cholesterol (often
called bad cholesterol), and triglycerides.
Sometimes the report will include additional calculated values such as HDL / Cholesterol
ratio or a risk score based on lipid profile
results, age, sex, and other risk factors.
How is a lipid profile used?
The lipid profile is used
to guide providers in deciding how a person at risk should be treated. The
results of the lipid profile are considered
along with other known risk factors of heart disease
to develop a plan of treatment and follow-up.
Lipid metabolism
Most of the
dietary fat is absorbed into the blood in chylomicrons. Triglyceride is removed
from the chylomicrons by lipoprotein lipase in the blood, fatty acids released
are taken up by the adipose tissue (Fat storage tissue) and the chylomicron
ramnants are removed by the liver. Triglyceride taken up by the liver is broken
down to 2-carbon fragments which are used in many metabolic processes. Free
fatty acids liberated by the adipose tissue is also taken up by the liver and used
in similar way.
In these processes lipid aggregates are formed
containing triglycerides, phospholipids and cholesterol. These are combined
with apoproteins to form Lipoproteins which are released into the blood.
These Lipoproteins are:
1. VLDL - Very Low Density Lipoproteins
2. IDL - Intermediate density Lipoproteins
3. LDL - Low Density Lipoproteins
4. HDL - High Density Lipoproteins
The density
of the lipoproteins is determined by the relative protein and lipid content with high density lipoproteins containing
high protein and fewer lipids.
The
liver synthesizes more cholesterol than any other organ. The cholesterol is
incorporated into lipoproteins or converted to bile acids or excreted into
bile. In biliary obstruction of any kind serum lipid
concentration increases mainly due to formation of abnormal lipoprotein known
as Lipoprotein X
What is cholesterol?
Cholesterol is a substance both made by the body and consumed in food products
that come from animals. Primarily, it travels in the blood as two compounds:
low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Lower
Cholesterol refers to LDL.
In practice, HDL is often called the 'good' cholesterol and LDL is called the
'bad' cholesterol.
The reason for this is that HDLs help transport cholesterol in the body to the
liver, where the body then prepares to excrete it. LDLs, on the other hand,
actually transport cholesterol from the liver to cells in the body.
Once the body's cells have all of the cholesterol they need, the extra cholesterol
can build up along blood vessel walls as plaque. People with high total
cholesterol to HDL cholesterol ratios want to Lower Cholesterol, are at
increased risk for heart disease because in general, they are transporting more
cholesterol to cells than they need.
Normal range
of cholesterol in the blood should be less than 200 milligrams per deciliter or
mg/dl. High cholesterol of 240 mg/dl or greater in the blood increases the
risk of heart disease, stroke, coronary artery disease etc. Abnormally low
levels of cholesterol may indicate hyperthyroidism, or an overactive thyroid
gland, liver disease, inadequate absorption of nutrients from the intestines
and malnutrition
Why Is It Important to Lower Cholesterol?
Lower Cholesterol is important to living a long and healthy life, one
that is free from heart disease or stroke.
Those are risk factors that come with elevated levels of cholesterol. The
health problems arise when there is too much total cholesterol and you want to Lower
Cholesterol in the blood because it can no longer move freely through the
arteries.
Over time excess cholesterol builds up against the artery walls and narrows the
space through which blood flows. This narrowing of the arteries is called
atherosclerosis
Care before the procedure
Avoid solid foods or drinks except water for 9 to 12 hours before taking
the blood sample for Lipoprotein analysis
(total cholesterol, LDL, HDL, and triglyceride levels).
How the test is done
Lipoprotein analysis or Lipid profile is
normally performed on a blood sample taken from a vein. This procedure takes
only a few minutes. The blood sample is collected in a syringe or vial and sent
to the lab to be analyzed. Total cholesterol levels may also be measured from a
finger-stick blood sample.
Age for Testing
Adults 20 years or over should be routinely tested every five years for
cholesterol, LDL, HDL and triglycerides. Children of parents with high
cholesterol over 240mg/dl should be checked regularly after age 7.
