Fasting For Blood Tests: Rules And Guidelines
If your doctor has confirmed that you should not eat anything before the test, you should not ignore their instructions. Here are some guidelines for fasting for a blood tests:
- It is important that you do not eat or drink anything but water. You should not eat anything at least 8 hours prior to your test. It is important to fast for at least 12 hours if your doctor has ordered lipid tests. Water is allowed though.
- You should not chew gum, smoke, or exercise before your test because all these activities can stimulate your digestive system and affect test results.
- Avoid alcohol for at least 24 hours before your test.
- You can take prescription medications unless your doctor advices against it. Certain medications, especially birth control pills can change your cholesterol levels, so you may want to stop taking them for a few days before the test. Your doctor may advise you to take the pills if they want to see its effect on your cholesterol levels.
It is important to note that you should fast for at least 8-12 hours depending on different tests, but avoid fasting beyond 14 hours because it will have a negative effect on the results. Just be sure to drink plenty of water to stay hydrated.
What Types Of Cholesterol Are There
There are two different types of cholesterol including:
- Bad Cholesterol which carry cholesterol particles throughout your body. LDL cholesterol is bad because it builds up in the walls of your arteries, making them hard and narrow which can increase the risk of a heart attack.
- Good Cholesterol which picks up excess cholesterol and takes it back to the liver. Having high HDL is linked to lower risk of heart disease, heart attack, and stroke.
When Should I Call My Doctor
If you develop new risk factors for cardiovascular disease, contact your healthcare provider. They may have you undergo a lipid panel or more frequent lipid panel screening.
A note from Cleveland Clinic
Seeing an abnormal test result can be stressful. Know that having an abnormal lipid panel result doesnt necessarily mean you need treatment. While cholesterol and triglyceride levels can play a significant role in your overall health, many other factors contribute to your risk for cardiovascular disease. Your healthcare provider will take many factors about your health and history into consideration when determining the next steps. Together you will decide on a plan that works best for you.
Last reviewed by a Cleveland Clinic medical professional on 11/09/2021.
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Can I Test My Own Cholesterol At Home
Its better to have your cholesterol tested by a professional because taking blood and measuring cholesterol levels is a skilled job and your results will be affected by the way you do the test. Going to a health professional means you will get an accurate reading.
We dont recommend home sampling, but if you do decide to test your cholesterol at home, follow these simple steps to take your sample safely and get a more accurate result.
Is There Anything Else I Need To Know About My Cholesterol Levels
High cholesterol can lead to heart disease, the number one cause of death in the United States. While some risk factors for cholesterol, such as age and heredity, are beyond your control, there are actions you can take to lower your LDL levels and reduce your risk, including:
- Eating a healthy diet. Reducing or avoiding foods high in saturated fat and cholesterol can help reduce the cholesterol levels in your blood.
- Losing weight. Being overweight can increase your cholesterol and risk for heart disease.
- Staying active. Regular exercise may help lower your LDL cholesterol levels and raise your HDL cholesterol levels. It may also help you lose weight.
Talk to your health care provider before making any major change in your diet or exercise routine.
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Who Performs A Lipid Panel Blood Test
A healthcare provider called a phlebotomist usually performs blood draws, including those for a lipid panel, but any healthcare provider who is trained in drawing blood can perform this task. A provider then sends the samples to a lab where a medical laboratory scientist prepares the samples and performs the tests on machines known as analyzers.
Fasting May Not Be Necessary Before Cholesterol Test
Before taking a cholesterol test, adults are typically told to fast for up to 12 hours or else levels in the bloodstream may be skewed by the recent meal. A new study, however, finds fasting may not be necessary after all.
The study, published Nov. 12 in the Archives of Internal Medicine, found the amount of time a person spent fasting prior to a cholesterol test had little impact on the end results.
“This finding suggests that fasting for routine lipid level determinations is largely unnecessary,” wrote the authors.
A cholesterol test, also called a lipid panel or lipid profile, measures the four types of lipids found in the blood, according to The Mayo Clinic. It measures low-density lipoprotein cholesterol, sometimes called “bad cholesterol” because high levels of it could lead to plaque buildup in the arteries, potentially causing a heart attack and stroke.
The test also measures high-density lipoprotein cholesterol, sometimes called “good cholesterol” because it helps carry LDL away from the blood. Cholesterol tests also measure total cholesterol and triglycerides, a type of fat found in the blood. People are typically told to have no food or liquids other than water for nine to 12 hours before the exam.
“This, in my opinion, tips the balance toward relying on nonfasting lipid profiles as the preferred practice,” he wrote.
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An Easy And Important Test
High cholesterol usually has no symptoms. Thats why its important to have your doctor check your cholesterol levels with a simple blood test.
It may be a “fasting” or “non-fasting” lipoprotein profile. Your doctor will tell you if you should fast before your test.
In the test, a health care professional takes a sample of your blood. If additional blood tests are needed, all the samples are usually taken at once. Discomfort is usually minor.
After the blood sample is taken, its analyzed in a laboratory, where the levels of HDL cholesterol, LDL cholesterol and triglycerides are measured. Your test report will show your cholesterol level in milligrams per deciliter of blood .
To determine your cardiovascular risk, your doctor will consider your cholesterol test results in context with your age, sex and family history. Other risk factors, such as smoking, diabetes and high blood pressure, will be considered as well. If your risk remains uncertain, and treatment options are unclear, your healthcare professional may consider other factors and/or request a coronary artery calcium measurement to provide greater insight into your risk and help in decision-making.
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. On that note, its definitely a good idea to tell your doctor about all medications and supplements youre taking to avoid something potentially skewing lab results.
Theres no indication that daily medications such as blood thinners and blood pressure meds will cause any problems with fasting bloodwork, so definitely continue taking them unless told otherwise. And if you have a headache, taking an ibuprofen or another over-the-counter pain reliever shouldnt cause any issues.
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What Happens Next
If you have high cholesterol, a doctor or nurse will talk to you about how you can lower it.
This might include things like changing your diet or taking medicine.
They may also work out your risk of having a heart attack or stroke in the next 10 years.
They can do this using your:
- cholesterol levels
How Long To Fast
Generally, you should fast for eight to 12 hours before lab work that requires it. Fasting for a blood sugar test, which is included in the basic metabolic panel, is generally eight to 12 hours.
You can always clarify how long to fast with your healthcare provider. If you are unsure, aim for 12 hours of fasting. For example, if you schedule your test for first thing in the morning, you should generally not eat anything after dinnertime the night before.
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Why Do Some Blood Tests Require Fasting
Certain blood tests require you to fast for 8-12 hours. The reason for asking you to fast is because when eat or drink beverages, certain nutrients, substances or vitamins enter into the bloodstream and can be responsible for giving a wrong result. Fasting before these advised blood tests ensures more accurate results.
Certain blood tests require you to not even drink water. Otherwise, drinking normal water will keep you hydrated and prevent your veins from collapsing, so drawing blood becomes easier since your veins are visible.
Avoid food, alcohol, soda or aerated drinks, tea, coffee, chewing gums and even exercising while fasting.
You need to consult your physician if you can take your regular dose of medications during fasting or adjust the dose timings for the purpose of fasting. This is because certain drugs can alter test results.
Why It Is Done
Cholesterol and triglyceride testing is done:
- As part of a routine physical exam to screen for high cholesterol and high triglycerides.
- To check your response to medicine.
- To help find your risk of having heart and blood flow problems, including heart attack and stroke.
- If you have unusual symptoms, such as yellow fatty deposits in the skin . These symptoms may be caused by a genetic disease that causes very high cholesterol levels.
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More Evidence That Fasting Not Needed Before Cholesterol Tests
This page was fact checked by our expert Medical Review Board for accuracy and objectivity. Read more about our editorial policy and review process.
A new analysis recently published in JAMA Internal Medicine adds to the evidence that people may not have to fast before blood tests to check their cholesterol and other lipid levels. Researchers from Brigham and Womens Hospital, Harvard Medical School, and Imperial College in London reviewed data from a study called the Anglo-Scandinavian Cardiac Outcomes TrialLipid Lowering Arm for their analysis.
Blood tests to check lipid levels, including total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels, are done routinely to help determine a persons risk of heart disease and to decide if and what treatment is necessary. Adults are usually instructed to fast for 9 to 12 hours before these tests, which are typically done together as a lipid panel.
The analysis found little difference between the fasting and non-fasting lipid results from the same individuals, according to the authors. The only difference was moderately higher triglyceride levels in non-fasting samples, which was expected. The researchers also found that fasting and non-fasting lipid levels had similar associations with coronary events. Non-fasting lipid levels reflected risk for heart disease similar to fasting levels.
What You Can Do About Abnormal Lipid Levels
Lifestyle changes are the first thing to tackle to reduce your chance of heart disease. Your doctor may also recommend that you start taking prescription drugs to help your cholesterol level.
Lifestyle habits to lower cholesterol
A cholesterol-lowering diet can bring down bad cholesterol by up to 30%. A diet low in saturated fat and simple carbohydrates and that has no more than 200 miliigrams of cholesterol daily can lower LDL cholesterol. Fiber and plant sterols help, too.
Keep these dietary tips in mind:
- Cut saturated fat to less than 7% of your total calories.
- Avoid trans fat completely. Check the ingredients label for âpartially hydrogenatedâ oils. Those are trans fats. Even if a product says 0 grams trans fat, it can have a small amount of trans fat , and that adds up.
- Read food labels. Products that say âlow cholesterolâ or âno cholesterolâ could be too high in saturated fats or sugar.
Regular aerobic exercise can lower bad cholesterol and raise good cholesterol . If you smoke, quit.
Lifestyle changes such as diet, exercise, and weight loss are also effective ways to improve your triglyceride levels. Ask your doctor for a sensible diet that will help. If you smoke, get suggestions on ways to help you quit.
Medications and procedures
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What Does The Test Result Mean
In general, healthy lipid levels help to maintain a healthy heart and lower the risk of heart attack or stroke. A healthcare practitioner will take into consideration total cholesterol results and the other components of a lipid profile as well as other risk factors to help determine a personâs overall risk of heart disease, whether treatment is necessary and, if so, which treatment will best help to lower the personâs risk.
In 2002, the National Cholesterol Education Program Adult Treatment Panel III provided the guidelines for evaluating lipid levels and determining treatment. However, in 2013, the ACC and AHA issued guidelines for adults that made recommendations on who should receive cholesterol-lowing therapy. .
However, use of the updated guidelines remains controversial. Many still use the older guidelines from the NCEP ATP III to evaluate lipid levels and cardiovascular disease risk:
For adults, in a routine setting where testing is done to screen for risk, the test results are grouped in three categories of risk:
For children and adolescents:
- A cholesterol below 170 mg/dL is acceptable.
- A result of 170-199 mg/dL is borderline.
- A total cholesterol reading greater than or equal to 200 mg/dL is considered high.
For young adults:
- A cholesterol below 190 mg/dL is acceptable.
- A result of 190-224 mg/dL is borderline.
- A total cholesterol greater than or equal to 225 mg/dL is considered high.
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Why Do I Need A Cholesterol Test
Cholesterol is a waxy, fat-like substance. Your liver makes all the cholesterol your body needs. But you take in more cholesterol from certain foods, such as those from animals. If you have too much cholesterol in your body, it can build up in the walls of your arteries and eventually harden. This process, called atherosclerosis, actually narrows the arteries, making it harder for blood to travel through the vessels.
Unfortunately, high cholesterol doesn’t cause symptoms. In later stages of atherosclerosis, though, you may suffer angina — severe chest pain from lack of blood flow to the heart. If an artery gets totally blocked, a heart attack results. A routine blood cholesterol test is a far better way of finding out what your cholesterol level is.
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Why Is High Cholesterol A Problem
Too much cholesterol in the bloodstream can harden arteries and promote fatty deposits within these arteries, potentially leading to dangerous blockages and narrowing over time called atherosclerosis.
If the blood vessels leading to your heart become too clogged, blood supply to your heart is reduced, which can lead to symptoms such as angina . If the artery becomes completely blocked, it can lead to a heart attack and stroke, which can be life threatening.
In 2017, the Australian Bureau of Statistics reported 43, 477 deaths in Australia from heart disease. This is approximately 30 per cent of all deaths in Australia, and most deaths are occurring in those aged 65 years and over.
However, heart disease takes years to develop, so you can take steps to reduce your risk.If you discover you have high cholesterol, have family members with high cholesterol, or are not sure if youre at risk, it is advisable you seek your doctors advice.
Other risk factors for heart disease include increased age, ethnicity, family history, inactivity, smoking, high blood pressure, type 2 diabetes and obesity.If these risk factors are present in your life, its even more important to keep your blood cholesterol levels in check and seek your doctors advice.
can help you begin to assess your risk, but we strongly advise you discuss your risk with your GP as this tool does have limitations it doesnt take your family history into account, for example.
Things To Do To Reduce Cholesterol Before The Blood Test
There are a handful of natural everyday modifications that you can implement into your daily routine to drop your cholesterol levels.
From full-fat dairy and sugary beverages to processed madness, you simply must avoid this range of food-types if you want to take cholesterol-lowering seriously.
- You can still consume meat. As long as you pair your meals with fresh fruits, whole grains, and veggies.
- Plants rich in fibre are excellent choices, particularly soluble fibre.
- Recommendations: berries, barley, beans , oats, yams.
In close connection to the previous point, consuming plant-based protein is a step in the best direction.
- Beans, beans, and more beans.
- Recommendations: Pinto, soy, lentils, red.
- Unlike animal protein, which raises blood pressure, beans are renowned for bringing it down.
- They also reduce blood sugar and insulin levels that have led scientists to believe beans play a significant role in cancer prevention and treatment.
If youve heard the name omega-3 fatty acids, then you can be sure the Diet-Universe has spoken to you.
- This is not just good fat, but great fat, owing in large part to how well it fights heart disease.
- Food sources: sardines, herring, salmon, trout, mackerel, halibut.
Below are some bad fats you absolutely need to avoid if you have any plans of getting your cholesterol under control.
You knew this point was going to land at your door sooner or later.
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