Testing HDL cholesterol can be achieved without the need to fast prior to the test (the food you eat during the day before the test would not have any affect of the HDL numbers), thus the results will still be accurate. However, in order to measure triglycerides and LDL, a 12-hour fasting is required before the test. During these 12 hours prior to your cholesterol test, you cannot eat and drink anything excluding water. The reason is that it normally takes about 9 to 12 hours for your liver to expel fatty particles from the blood.

Since most high fat foods contain high levels of triglycerides (which are a cardinal part of the cholesterol test), by taking no fat, no calories and restricting your consumption to water alone for 12-14 hours prior to the cholesterol testing, you ensure the figures will be most accurate.

Drinking plenty of water is very important during the fast before the cholesterol test both as a cleansing protocol and as to make the cholesterol measure more accurate. The water will help the body remove triglycerides out, prior to the test making the triglecerides numbers more accurate.

Bear in mind however, that in not so common cases where your triglycerides level is above 400, your LDL blood level will be tested alone since your high level of triglycerides is of no use to measure LDL.

Accuracy is not always achieved when testing blood cholesterol levels. In some cases you’ll get bold inaccurate results. There can be many error in cholesterol measurements, for example: an extreme increase in LDL levels compare to your last annual test is usually an indication of a technical error. The only way to be sure the results of your blood cholesterol test are in fact the correct results, a second and even a third test should be taken. Your doctor will usually make an average of the second and third test in case the numbers are no more than 30 points apart.