High blood cholesterol, the condition, keeps a very low profile. Typically, no signs or symptoms make themselves known in the people it sneaks up on. And yet, its consequence can be dire. High blood cholesterol increases risk of heart disease, the leading cause of death in the U.S.

Only a blood test can detect when levels of the waxy blood substance called cholesterol have reached unhealthy limits. From your arm, a sample of blood will be drawn, then studied by a laboratory.

A check-up at the doctor’s office is often a good place to have a cholesterol test (also called a lipid profile or lipid panel). That’s because your doctor already has all of your medical information on file and will be able to consider your cholesterol-test results alongside any known risk factors of heart disease you may have including age, family history, and/or smoking. It’s on consideration of all this data, not just the results of your cholesterol test, that your doctor can make appropriate prevention, follow-up, or treatment recommendations.

Your doctor will advise you whether or not to fast (refrain from eating and drinking) prior to the cholesterol test; and, if so, for how many hours (typically it’s between nine and 12). Only total cholesterol and HDL (good) cholesterol levels will be available for consideration if you do not fast. That’s because food, drink, and medications taken recently before a cholesterol test can alter levels of LDL (bad) cholesterol and triglycerides (blood fats).

If a test done without fasting shows certain results (for example, total cholesterol of 200 mg/dL or more, or HDL (good) cholesterol of 49 mg/dL or lower if you’re a woman and 39 mg/dL or lower if you’re a man) your doctor may request you take a follow-up test with fasting.

It is generally recommended that everyone in the U.S. have his or her first fasting lipoprotein profile (also called lipid profile or lipid panel) at age 20 and, if levels are satisfactory, every five years.

Your doctor may advise more frequent screening if certain factors such as those listed below apply to you:

  • You’re a man age 45-plus or a women age 50-plus (cholesterol levels rise naturally with age)
  • You have risk factors for heart disease
  • Your HDL is 49 mg/dL for women, 39 mg/dL or lower for men