Avoiding specific foods and drinks such as cooked meats, herbal tea, or alcohol. Making sure not to overeat the day before a test. Not smoking. Avoiding specific behaviors such as strenuous exercise or sexual activity.
Preparing for a blood test
avoid eating or drinking anything (fasting) apart from water, for up to 12 hours – read more about eating and drinking before having a blood test. stop taking certain medicines.
Non-prescription drugs (aspirin, cold medication, vitamins), prescription drugs, and alcohol intake often affect blood test results. Your medical practitioner must have a complete and honest picture of your use of medications in order to effectively interpret the results of your blood tests.
Ideally, start drinking more fluids the day before your blood draw, and continue to drink water before you have your blood drawn. Excessive amounts aren't necessary; most sources ecommend that an adult drink 64 ounces of water per day for good health, which is more than adequate for having your blood drawn.
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.
Water does not affect the results of a blood test and is acceptable to drink when a person needs to fast.
How long do I have to fast before the test? You usually need to fast for 8–12 hours before a test. Most tests that require fasting are scheduled for early in the morning. That way, most of your fasting time will be overnight.
The healthcare professional arranging your test will tell you if you need to do anything to prepare for it. 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.
Don't eat or drink anything except water for 8 to 12 hours before getting the blood test. Do not stop any medication without consulting the doctor. Don't eat heavy, fatty, and fried food items 1-2 days before the test day.
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.
Blood tests should be performed in the morning. For tests that measure blood sugar, blood fats, liver and kidney function tests, patients need to fast for 8-12 hours before to get the most accurate results.
For fasting sugar you cannot eat anything. For post prandial you can eat a banana before the test.
What happens if I don't fast before a blood test? If you don't fast before a test that requires it, the results may not be accurate. If you forget and eat or drink something, call your doctor or lab and ask if the test can still be done. They can then tell you if you need to reschedule your test.
Blood tests
You will usually have a fasting blood test in the morning after you have fasted for 10 to 12 hours (no less than 8 hours and no more than 16 hours).
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.
Effect of Dehydration in a Lab Blood test and Blood pressure
Due to dehydration, there can be inaccurate blood test results as suspected, as water accounts for approximately 60% of the adult human body weight. So, lack of water may lead to dehydration and thus affect blood pressure and blood test results.
That's why a fasting blood test usually requires fasting for 8-12 hours before your blood is taken. It's also recommended that you avoid alcohol for 24 hours before your test, as well as any strenuous exercise.
Yes, it is possible for dehydration to skew the results of a cholesterol test. This is attributed to the fact that dehydration can cause blood volume to decrease, leading to a drop in blood pressure and blood flow.
What can a person eat the night before? If a healthcare professional has asked a person to fast, they should not consume anything other than water the night before a cholesterol test. Fasting means that a person can only consume water for the hours before their test.
Does what you eat before the test matter? Consuming a double cheeseburger, fries, and a milk shake right before having your blood drawn for a cholesterol test may lead to a follow-up fasting test if the triglycerides are very high. But eating normally has little effect on your lipid levels, including triglycerides.
Cheese and crackers, peanut butter, nuts like walnuts, cashews, almonds, or peanuts, or a healthy sandwich are all good options. Additionally, vitamin B12 aids your body in regenerating red blood cells and nerve cells, meaning foods containing it make great snacks after you have your blood drawn.