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...
Quick Answer. According to Quest Diagnostics, a lipid or glucose tolerance test requires eight hours of fasting. Health care providers may have other recommendations, depending on the type of test. Fasting means consuming no food or beverages, except water, for several hours, explains Quest Diagnostics. Fasting is often required before blood tests because nutrients in food and drink can absorb in the bloodstream, affecting the test results. Not fasting before such tests may yield inaccurate results.