Q: Can you take medication before a fasting blood test? A: You can take over-the-counter and prescription medications unless your doctor advises you otherwise.
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.
Your doctor may ask you to not eat or drink anything except water for 9 to 14 hours before the tests. In most cases, you can take your medicines with water the morning of the test.
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. Take your prescription medications unless your doctor tells you to skip them.
Pre-Test Preparation
On the morning of the test: no water or any form of drink, no food, no gum and no smoking. Teeth may be brushed but you must not swallow. Stop all antacids during the fasting period.
If your health care provider has told you to fast before a blood test, it means you should not eat or drink anything, except water, for several hours before your test.
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.
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.
In most cases, you will need to fast for 10-12 hours before your cholesterol test. Fasting means not drinking or eating anything except for water. Foods you eat can affect the levels of triglycerides in your blood, which can alter the outcome of the blood test.
High cholesterol levels are considered: too high: between 5 and 6.4mmol/l. very high: between 6.5 and 7.8mmol/l. extremely high: above 7.8mmol/l.
Taking statins? Sorry — time to sit out mealtime. Statins like Lipitor, Lipostat, and Zocor are drugs that help lower cholesterol. If you take cholesterol meds, you'll likely have to fast for 9 to 12 hours before the test to avoid skewed results.
Most of the time, it's advised to take regular medications before a fasting blood test. Often, it's advised to continue taking your regular medications, even before a fasting blood test. But, its always good to clear this with your doctor, as well as any vitamin or supplements that you take on a daily basis.
Sometimes certain factors can affect your test results, such as pregnancy, a medicine you are taking, eating right before a test, smoking, or being under stress. When your lab numbers are lower or higher than the numbers in the reference range, further testing may be needed.
Drinking water before a fasting blood sugar test can actually decrease blood sugar levels, or at least prevent levels from getting too high. Water allows more glucose to be flushed out of the blood. When you're dehydrated, it means your overall blood volume is lower than normal, but your sugars will be the same.
Like many other blood tests, cholesterol tests require a fasting period beforehand. According to the CDC, most cholesterol tests (called “lipid panel” or “lipid profile”) require you to fast for 8 to 12 hours.
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.
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.
a fasting blood glucose test (used to test for diabetes) – you may be asked to fast for 8 to 10 hours before the test.
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.
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.