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...
Doctors also use them to figure out how well treatments are working. You don't need to fast before all blood tests. Your doctor will tell you if you need to. These tests typically require fasting: Fasting blood glucose measures the amount of glucose in your blood to test for diabetes or prediabetes. Typical fasting time: At least 8 hours Lipid profile is used to check the level of cholesterol and other blood fats.