For Accurate Blood Test Results: Fast There is good reason your doctor recommends not eating or drinking: to attain the most accurate blood test results. Nutrients and ingredients in the food and beverages you eat and drink are absorbed into your bloodstream. This could impact factors measured by certain tests.
“Because eating can raise your blood sugar, triglyceride and cholesterol levels, if you eat before the test, you may need to come back another time,” says Dr. de Ridder. Drink plenty of water before your blood test. Staying hydrated helps increase your blood volume.
If your appointment is at 8 a.m. and you're told to fast for 8 hours, only water is OK after midnight. If it's a 12-hour fast, avoid food and drink after 8 p.m. the night before. You also shouldn't smoke, chew gum (even sugarless), or exercise. These things can rev up your digestion, and that can affect your results.
You can eat and drink as normal before some blood tests. But if you're having a "fasting blood test", you will be told not to eat or drink anything (other than water) beforehand. You may also be told not to smoke before your test.
Water does not affect the results of a blood test and is acceptable to drink when a person needs to fast. Timings: Whether a person has to fast for 8, 12, or 24 hours, it is a good idea to work out what is the latest time they can eat or drink before the test.
Ideally, start drinking more fluids the day before your blood draw, and continue to drink water before you have your blood drawn.
If permitted to drink water, aim for the recommended daily amount of 64 ounces and have a glass of water (approximately 16 ounces) before your donation.
McKnight also mentioned the food or drinks you consume the day or night before a blood test does not impact your test results, unlike what you eat or drink the morning of your test. “It's recommended that you avoid coffee and other liquids during your fast,” McKnight said.
Do not eat and do not drink juice, tea, or coffee, especially with sugar, 10-16 hours prior to blood tests (depends on the type of test). Drink water only. 3. Eat less greasy and fried food and do not drink alcohol 1-2 days prior to the test.
Alcohol can also affect blood sugar and fat levels, giving inaccurate results to blood tests that require fasting. If a person is being asked to fast before a blood test, they should also refrain from drinking alcohol.
Abnormal results may be the result of several factors and do not always indicate the presence of any disease. Some of these factors are: a) you ate too soon before your blood was drawn; b) medications you are taking; c) you are normally not within standard ranges.
Walking and gentle yoga are fine. Do not perform any exercise except gentle walking on the morning of the test. Strenuous exercise and exercise in the hours before the test can affect liver enzymes, white cell counts, zinc, cortisol and many others.
Effect on Lab Results: If you eat sugar before getting your blood sugar tested, you will get an inaccurate reading. Instructions: Taking iron pills or tablets for 24 hours before the test should be avoided.
You have to fast for about 10 hours before the test because triglyceride levels can shoot up 20%–30% after a meal, which would throw off the equation. Alcohol also causes a triglyceride surge, so you shouldn't drink alcohol for 24 hours before a fasting cholesterol test.
You're generally required to fast, consuming no food or liquids other than water, for nine to 12 hours before the test.
The best foods to eat are those that are rich in iron, including fortified cereals and leafy vegetables like spinach. Meat that includes iron includes fish, eggs, and poultry. Vitamin C improves your body's ability to absorb iron, so citrus or bell peppers also make good complimentary snacks.
The answer depends on two factors – the type of blood test you're taking, and the kind of coffee you drink. Certain types of blood tests will require you to abstain from coffee, among other kinds of food and drink, for several hours to ensure that your test results are accurate.
1. Coffee Affects Your Blood. A small amount of coffee can alter your blood test results. Levels of electrolytes and gastric pH can become affected, as well as your cardiac frequency and blood pressure.
When you drink a glass of water, it takes approximately 15 minutes for your body to absorb the fluid. However, when you're dehydrated, it can take about three times as long (45 minutes) for fluids to make their way from the stomach into the bloodstream and to the rest of the body.
Have nothing to eat or drink for at least 10 to 12 hours - preferably an overnight fast. If you are thirsty, sips of plain water only are permitted.
Blood Tests for Dehydration
Skyrocketing hematocrit levels – The hematocrit test gauges the percentage of red blood cells in your blood. High levels could imply there's not enough water cruising through your veins. Elevated blood urea nitrogen (BUN) – BUN measures the amount of urea nitrogen in your blood.