Blood tests can help your doctor determine risk for disease, diagnose disease or follow the progress of treatment. Two common blood tests are a lipid panel and blood glucose test. A lipid panel, also called a coronary risk profile, is used to help determine risk for heart disease. Lipid panels include total cholesterol, low-density lipoprotein, or LDL, high-density lipoprotein, or HDL, and triglycerides. Blood glucose levels are used to diagnose diabetes, or if you have diabetes, help to determine if it is well-controlled.
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A lipid panel measures different types of fats in the blood. It is performed after a nine to 12 hour fast, meaning you cannot eat or drink anything in that time frame. The American Heart Association recommends a first screening test for all adults age 20 or older and every five years thereafter. Your doctor may recommend more frequent testing depending on prior blood test results, your age or if you have other risk factors for heart disease or stroke.
Cholesterol is a type of lipid. It is a wax-like substance found throughout the body. Some cholesterol is needed for various functions in the body, including making the sex hormones and vitamin D. Cholesterol is found in animal fats and is consumed in the diet, but the liver makes cholesterol, as well. Too much cholesterol in the blood can clog your arteries. A desirable total cholesterol is under 200 mg per deciliter, or mg/dL; borderline high is 200 to 239 mg/dL; and high risk is 240 mg/dL or higher.
LDL and HDL
Since the blood is made of water, the lipids need a “carrier” to take them from place to place in the body. LDL and HDL help transport cholesterol, triglycerides and other fats. LDL is referred to as “bad cholesterol.” An optimal LDL range is less than 100 mg/dL or less than 70 mg/dL for individuals with a history of heart disease or at high risk for atherosclerotic disease. HDL, also called “good cholesterol,” carries lipids from various parts of the body back to the liver. An HDL of 60 mg/dL helps protect against heart disease. Risk for heart disease increases if HDL is less than 40 mg/dL.
When you eat too many calories you body makes triglycerides, the storage form of fat. High triglycerides can lead to atherosclerosis, or hardening of the arteries, which increases risk for heart attack and stroke. Normal triglycerides are less than 150 mg/dL, borderline high from 150 to 199 mg/dL, high from 200 to 499 mg/dL and very high is considered 500 mg/dL or higher.
Blood glucose is also referred to as blood sugar. Your doctor may order a fasting blood glucose test, with no eating or drinking for eight hours before the test. A normal fasting blood glucose is between 70 and 99 mg/dL. You may have prediabetes, also called impaired fasting glucose, if your levels are between 100 and 125 mg/dL. Diabetes is diagnosed with a fasting blood glucose that is 126 mg/dL or higher on more than one occasion.
REFERENCES & RESOURCES
- MedlinePlus: Cholesterol Test; June 2010
- MedlinePlus: LDL Test; May 2010
- MedlinePlus: HDL Test; May 2010
- MedlinePlus: Triglyceride Level; May 2010
- MedlinePlus: Glucose Test; May 2010
- "Marks' Basic Medical Biochemistry: A Clinical Approach, 3rd Edition"; Lieberman and Marks; 2008
- American Heart Association: What Your Cholesterol Levels Mean; Februray 2011
- American Heart Association: How to Get Your Cholesterol Tested; January 2011