For the study, researchers compared cholesterol testing results of 300,000 people from Denmark, Canada, and the U.S. In both the U.S. and Canada, fasting for eight hours before a test is required. In Denmark, however, it is not.
Patients who are scheduled for a lipid profile test should fast (except for water) for 12-14 hours before the blood sample is drawn. If the patient's cholesterol is to be fractionated, he or she also should avoid alcohol for 24 hours before the test. http://www.healthatoz.com/healthatoz/Ato...
Tests that Require Fasting. Blood cholesterol, triglyceride and glucose levels are the most common tests that require fasting. Vitamin levels, such as vitamin E or A, also need to be drawn when the patient is fasting. Time Frame. Typically at least a 12-hour fast is required for cholesterol and triglyceride screenings.