Is It OK to Drink Coffee When Fasting for Blood Work?

drinking coffeeBefore you undergo a blood test, the doctor will tell you not to eat or drink anything for several hours. Sometimes, he will tell you not to eat anything for 12 hours prior to the test. This fasting for blood work can be difficult for those people who love to drink coffee early in the morning. In this article, let us try to find out if you can drink coffee before having a blood test.

So, can you really drink coffee when fasting for blood work? This may be a tricky question because some doctors will tell you that it is OK to drink tea of coffee as long as there is no sweetener involved. However, there are some blood test results that were inaccurate brought by coffee and tea. Therefore, it is advisable to avoid them when you are fasting for blood work. Yes, you can drink water, but you should avoid other things like gum or cigarettes. It is also not advisable to have an exercise.

It Might Interfere Your Blood Sugar Value

blood sugar value

Though several tests might be accurate when drinking coffee before the test, the fasting blood sugar test will not be. FBS or fasting blood sugar, measures the amount of glucose in the blood. This is actually used when you are being examined for diabetes or other ailments. The reason behind drinking coffee before the test is that coffee can be absorbed by the body very fast, especially when caffeine is present. Caffeine can boost blood sugar levels and it can give an inaccurate result on the FBS test. In addition, coffee beans are actually made of 40% sugar. This means that you are consuming additional sugars into your system even when there is no sweetener present in your black coffee. This is already enough to mess up your results.

Coffee Can Affect the Function of the Liver


Caffeine can also affect the function of the liver as it can signal the body to release hormones. This can affect your pancreas, insulin, and any other elements. How about decaf coffee? Unfortunately, even decaf coffee still has caffeine present in it. Therefore, you cannot have decaf coffee as well.

So, How Should You Fast?

how to fast

For around 8 to 12 hours fasting for blood work, steer clear from drinking or eating anything else but plain water. Do not add flavoring in your water. If you are having some medications that you normally take, inquire to your doctor if you should take them or skip them before the scheduled test. If you are taking insulin, then you might be asked to adjust or skip it.

Lastly, How Should You Prepare for the Test?

how to prepare

You should east nutritious food before fasting for blood work starts. Once you did it, it is water that you only have to consume before the blood test unless your doctor told you to take anything else. So since you will be going without eating any food, it would be a good idea of prepare a good snack once the blood test is done. So in general, drinking coffee, tea, or any other beverages should not be taken before the test because some changes will happen in your blood.

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