Clinical definition of the Cholesterol test
Cholesterol is a natural waxy, fatlike substance present in the cell membranes of the body and is mainly produced in the liver (about 70%). Small amounts of cholesterol are needed for the normal body functioning, such as for the manufacture of important components such as bile acids, steroid hormones, and fat-soluble vitamins including Vitamin A, D, E, and K. The excess amounts may be deposited in the walls of the artery throughout the body. These depositions can lead to narrowing of the arteries in the heart, causing angina and heart attack; narrowing in the carotid arteries that supply blood to the brain, causing stroke; and narrowing of the femoral arteries supplying the legs, causing peripheral artery disease. Cholesterol can't dissolve in the blood. It has to be transported to and from the cells by carriers called lipoproteins. Low-density lipoprotein, or LDL, is known as "bad" cholesterol. High-density lipoprotein, or HDL, is known as "good" cholesterol. These two types of lipids, along with triglycerides, make up your total cholesterol count, which can be determined through a blood test.
Why is the Cholesterol test done?
Cholesterol is an important and necessary molecule for humans. However, it is important to measure these blood fats to determine the risk of a cardiovascular disease, since a high level of serum cholesterol is an indicator for such diseases.
A series of tests i.e. a lipid profile may be done to determine the amount of fat in the blood. Each of these components is important in determining your risk for heart disease.
There are five major fat components that would be tested in the lipid profile:
- Total cholesterol
- Low-density lipoprotein (LDL)- "bad" cholesterol
- High density lipoprotein (HDL)- "good cholesterol"
- Very low density lipoprotein (VLDL)- often calculated from the triglyceride level
- LDL/HDL Ratio (calculated values)
- Total cholesterol/HDL Ratio (calculated values)
What are the common signs/symptoms when the Cholesterol test is done?
- Shortness of breath
- Pain, fullness, and/or squeezing sensation of the chest
- Jaw pain, toothache, headache
- Nausea, vomiting, and/or general epigastric (upper middle abdomen) discomfort
- Heartburn and/or indigestion
- Arm pain (more commonly the left arm, but may be either arm)
- Upper back pain
- General malaise (vague feeling of illness)
Who should do the Cholesterol test (Target population)?
It may be ordered more frequently for those who have may have risk factors for heart disease such as:
- Age (men 45 years or older or women 55 years or older)
- Overweight or obese people
- Heavy drinkers
- People with a family history of heart disease or health problems such as diabetes, high blood pressure (hypertension),
- People who consume excess of saturated fats - found mostly in animal products and trans-fatty acids -found in fast foods and commercially processed food products.
- Pre-existing heart disease or those who have already had a heart attack
What should I do before the Cholesterol test?
Specimen collection procedure
Preparatory instructions during specimen collection*
Serum (Blood Sample)
Venipuncture - Collection of blood from a vein, usually from the arm.
Fasting samples have to be collected after a minimum 12-14 hour overnight fasting status.
Clear fluids like water is allowed during this period. Refrain from consumption of early morning beverages like tea, coffee and milk until specimen collection is completed.
In case of diabetics on oral or injectable hypoglycemic agents, consult your physician about continuing with these medications prior to specimen collection.
* Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.
How do I interpret my Cholesterol test results?
less than 200 mg/dL
240 mg/dL and above
Inference: Heart disease risk factors which can be changed include high blood cholesterol, high blood pressure, cigarette smoking, obesity, and sedentary lifestyle. Those risk factors which cannot be changed include family history, gender and advancing age (men >45; women >55). Diabetes is a risk factor that in some cases can be changed or controlled.
‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’
Diseases/conditions related to the Cholesterol test
- Heart attack
- Peripheral artery disease
- Arteriosclerosis of the extremities
- Familial dysbetalipoproteinemia
- Familial hypercholesterolemia
- Kidney disease
- Liver disease
- Type 1 or Type 2 diabetes
- Primary biliary cirrhosis
Other tests related to the Cholesterol test
- HDL Cholesterol
- Lipid profile
- Apolipoprotein A-1
- Apolipoprotein B (APO-B)
- Cardiac risk profile