By Sharon Stewart Blake, Tests.com Contributing Writer
Cholesterol is a waxy fat-like substance produced by the human body and necessary for many bodily functions. Excess cholesterol in the bloodstream can be deposited in the arteries, which can be a major risk factor stroke or for heart disease, the leading cause of death in the United States. According to the Center for Disease Control in America, 17 percent of adult Americans have high blood cholesterol (240 mg/dL or more total cholesterol). Cholesterol testing is used to estimate one’s risk of developing heart disease and is a routine part of preventative health care.
Cholesterol can be found in cell walls throughout the body. Humans need it to produce Vitamin D, hormones, cell membranes and the bile acids that help to digest fat. Our bodies already make enough cholesterol for those needs. The rest of the cholesterol in the body comes from our diet. Food from animals—butter, eggs, meat, regular and low-fat milk— and foods with saturated fats and trans fats contribute to high cholesterol levels.
Because it cannot dissolve in the bloodstream, cholesterol moves through the body via carriers called lipoproteins. Low-density lipoproteins or LDL is called bad cholesterol, while high-density lipoproteins or HDL is called good cholesterol.
Excess bad cholesterol is deposited in the arteries, including those that feed oxygen-rich blood to the heart to maintain its health. Too much LDL can cause a thick substance called plaque which hardens the arteries or clogs them altogether. This thickening is a condition called atheroscolerosis.
The good cholesterol actually protects the heart. These lipoproteins move cholesterol away from the arteries to the liver, where it is broken down.
Triglycerides are another form of fat made in the body and too much of it can be due to obesity, smoking, physical inactivity, excessive alcohol consumption and a diet high in carbohydrates. A person with high triglycerides usually has a high total cholesterol level, which would include high levels of LDL and a low amount of HDL.
Types of Cholesterol Tests
It is advisable for a doctor to conduct the test because he or she already has a lot of the necessary information about a person’s family history, smoking and lifestyle that can assist in the development of a treatment plan.
Home cholesterol tests have been approved by the FDA but vary slightly in accuracy. Cholesterol testing kits traceable to a program of the Centers for Disease Control and Prevention are believed to be the most accurate.
A test for cholesterol may also be available at a health fair. The American heart Association advises us to make sure a company doing a public screening is a reputable one. Results of a health fair test or at-home test should be shared with a doctor.
A full cholesterol screening is called a lipid profile or cardiac risk assessment and includes estimates of your total cholesterol—LDL and HDL levels—and triglycerides. A doctor may also just test for a total cholesterol level and HDL levels.
The newest type of cholesterol test—the VAP® (Vertical Auto Profile) Test—uses technology that can report an expanded profile of 15 to 20 separate components of blood cholesterol, as opposed to only four in a standard test. Developed at the University of Alabama in Birmingham and manufactured by Atherotech, Inc., the test is the first to comply with recommendations calling for more accurate, direct, LDL measurement, unaffected by triglycerides. The test also identifies markers for metabolic syndrome, a precursor for diabetes. The price of the VAP® Test is comparable to the traditional cholesterol test.
During a cholesterol test, a doctor or nurse removes a blood sample from a vein inside the patient’s arm near the elbow. The sample is sent to a lab to be analyzed. In cholesterol home test kits, the patient pricks his fingertip with a lancet and applies the blood sample to a special type of paper which then changes color depending on the amount of cholesterol in the blood.
Who Should Take a Cholesterol Test?
Cholesterol screening tests are advisable for every adult over 20. Because cholesterol levels increase with age, postmenopausal women and men in their 50s or 60s should get a test. Cholesterol blood tests may also be ordered for patients more at risk for heart disease—those who smoke, are overweight, have high blood pressure, diabetes, a family history of heart disease or who have already had a heart attack. Even high-risk children should get a full lipid profile. The American Academy of Pediatrics suggests the first profile be ordered for a high-risk child between the ages of two and 10. High cholesterol levels have no symptoms.
Adults over 20 are advised to have a cholesterol test taken every five years. Those who are on cholesterol-lowering medication will most likely have a test several times a year, because the physician wants to monitor how well the medicine is working.
Precautions and Preparation
Patients getting a complete lipid profile are usually asked to fast for nine to 12 hours beforehand. This is because levels of triglycerides and LDL are affected by foods we consume. Patients only getting a cholesterol test do not need to fast. If a patient does not fast before a complete lipid profile, only the HDL and total cholesterol levels will be of use. Check with your doctor if unsure what to do before an at-home test.
Patients should not be tested while sick because cholesterol levels are low during acute illness, immediately after a heart attack or during stress related to an accident. It is also advisable to wait six weeks after giving birth to get tested because cholesterol is high during pregnancy. There are some drugs that can affect cholesterol levels, including steroids, beta blockers, epinephrine, birth control pills and vitamin D.
Cholesterol Test Results
Cholesterol is measured in milligrams (mg) per deciliter (dL) of blood. The result is a number.
For total cholesterol screenings:
Under 200 milligrams per deciliter (mg/dL) Desirable
From 200 to 239 mg/dL Borderline High
240 mg/dL and higher High Risk
For LDL cholesterol levels:
Less than 100 Optimal
100 - 129 Near Optimal
130 - 159 Borderline High
160 - 189 High
190 and above Very High
For HDL cholesterol, the higher the number, the better:
60 and above High/Optimal
Less than 40 in men/less than 50 in women Low/At Risk
A high triglyceride level has been linked to coronary artery disease in some people.
Less than 150 Normal
150 - 199 Borderline High
200 - 499 High
500 or higher Very High
Are you interested in a cholesterol test? Please visit our Cholesterol Test Directory.