Total Cholesterol

What is total cholesterol?

Cholesterol is a fat-like substance needed to build cell membranes, to produce some hormones and vitamin D, and to form bile acids, which help digest fats. Most of the cholesterol in the body is produced in the liver; the rest comes from animal foods such as meat, dairy products and eggs. Because cholesterol does not dissolve in water, it circulates in the blood in carrier particles called lipoproteins.

Total cholesterol is the sum of the cholesterol in all these carriers; in other words, it shows the cholesterol in LDL, HDL and VLDL together. For this reason it gives a general picture on its own, but an accurate risk assessment requires knowing which fraction is high. The measurement is made on the serum portion of blood drawn from the arm using enzymatic methods and is usually part of a panel called the lipid profile.

When is a total cholesterol test ordered?

High cholesterol can contribute to plaque buildup in the arteries for years without causing any symptoms. This is why total cholesterol is ordered as part of regular health check-ups in adults, and especially in people at risk of cardiovascular disease. In children and young people with a family history of inherited high cholesterol, it may also be measured at an earlier age on a doctor's recommendation.

• Routine health check-ups at regular intervals in adults
• Family history of high cholesterol or early-onset heart disease
• Risk factors such as diabetes, high blood pressure, smoking or excess weight
• Monitoring the response to diet, exercise or medication
• Conditions that can affect cholesterol, such as thyroid or kidney disease

How do you prepare for a total cholesterol test?

Total cholesterol is only slightly affected by meals; however, because the test is mostly ordered together with triglycerides and LDL, 9–12 hours of fasting is usually recommended. During this time it is best to drink only water and leave tea and coffee until after your blood has been drawn. If your doctor has ordered only total cholesterol and HDL, the measurement can also be done after eating; follow the instructions you have been given.

Avoiding alcohol the day before the test and not changing your usual diet help ensure that the result reflects your everyday state. A recent illness with fever, surgery or a serious infection can temporarily lower cholesterol levels; in this case your doctor may suggest doing the test a few weeks later. Unless your doctor tells you otherwise, keep taking your cholesterol medication as usual. You can schedule your blood draw for early in the morning, at your home or workplace.

What does a total cholesterol result mean?

High total cholesterol may be associated with a diet rich in saturated and trans fats, physical inactivity, excess weight, inherited predisposition, an underactive thyroid gland, some kidney and liver diseases, or certain medications. Cholesterol also rises naturally during pregnancy. However, a high total cholesterol does not always mean something negative; a high HDL cholesterol can also increase the total value.

Low total cholesterol, on the other hand, can be seen in conditions such as an overactive thyroid gland, severe liver disease, malabsorption disorders or malnutrition. Your doctor calculates your personal risk by evaluating the result together with your LDL, HDL and triglyceride values and with risk factors such as your age, blood pressure, smoking and diabetes. The limits used for cholesterol may vary by laboratory, age and sex, and your personal target may differ from these limits; this page shows the range of the laboratory that runs your test. Your result should be interpreted by your doctor together with your medical history, any symptoms and your other lipid tests, and it is your doctor who should decide whether treatment is needed.