Blood testing is done to check the blood for abnormalities, including high cholesterol and glucose levels. Before going to a hospital or doctor's office for testing, people often wonder if they can eat or drink before the blood test. Your healthcare professional who arranged for your testing will let you know if you can eat or drink within 12 or 24 hours of testing. If you are unable to eat or drink anything other than water within a few hours of testing, you will be taking what is referred to as a fasting blood test. However, for some tests, eating or drinking before the test will not affect the results. Other blood tests require that you abstain from smoking or drinking alcohol within 24 hours of testing. Following are the required preparations for several common blood tests.
A triglyceride test measures the amount of the lipid, or fat, in the blood. Triglycerides are converted from calories to store fat in your cells. The triglycerides are released to provide energy for your body in between meals. Consuming more calories than you typically burn each day builds up the levels of triglycerides in your body, increasing your risk of getting heart disease. A triglyceride test is a fasting blood test.
A cholesterol test, also called a lipid profile or panel, is used to measure the levels of cholesterol in the blood. Since high cholesterol levels in the blood typically have no symptoms, a blood test is the only way to determine if levels are high. Cholesterol causes plaque to form in arteries, contributing to heart disease. A cholesterol test is a fasting blood test.
Glucose tests measure the amount of glucose, or sugar, in the blood. High levels of glucose indicate diabetes or a pre-diabetic condition. Those who have the disease also undergo blood glucose testing regularly to make sure that treatment is working. A glucose test is a fasting test.
A lack of essential vitamins can cause numerous problems. A vitamin level test can check the blood for the levels of certain vitamins, including vitamins A, D, and B12. Depending on the reason your healthcare professional has recommended this fasting blood test, levels of other vitamins and nutrients may be tested as well. A vitamin level test is a fasting test.
An iron test checks the levels of iron that are in the blood, which determines how well your body is metabolizing iron. Iron is needed for hemoglobin production, which allows the red blood cells to carry oxygen throughout the body. Low iron can result in anemia. Because iron is not produced in the body, it must be taken into the body through the diet or supplements.
A GGT test measures the levels of gamma glutamyl transferase in your blood. GGT is a liver enzyme that, under normal conditions, is found only in the liver and other organs. If GGT is present in the blood, it is an indication of liver disease that has allowed the enzyme to leak from the liver and into the bloodstream.