Why Do You Need To Fast Before A Blood Sugar Examination?

Well, you do not actually need to fast for a random blood sugar examination. However, if the requested examination is fasting blood sugar or FBS, then you need to undergo a NPO procedure (non-per-orem or nothing by mouth).

“Did you fast?”

A laboratory scientist or a nurse will ask you this question before extraction. If you said no, then you could not proceed as the result would surely show a falsely elevated FBS.

What is FBS anyway? 

Fasting blood sugar is a screening test for diabetes. Because it is a screening examination, your doctor may recommend other examinations, like A1C test, that can confirm whether or not you have diabetes.

Why should you undergo fasting for 8 hours?

You must fast for six to eight hours to clear your system before the examination. In person with no diabetes, it usually takes two to five hours before the blood sugar level would return to normal after eating. So, if you did not take anything (except water) for six to eight hours before collection of blood, then your fasting blood sugar result would be accurate.

What are the normal values for this examination? 

According to the American Diabetes Association, the normal values for fasting blood sugar would be from 70 mg/dL to 99 mg/dL. But these values may vary from one laboratory to another, depending on the methods used by the laboratory to analyze the analyte.

If your FBS result is slightly higher than normal, then your doctor may request for another fasting blood sugar test to confirm the result.

Do not discuss your result with the laboratory scientist

Most of the time, patients do ask a nurse or a laboratory scientist to know what their results mean. Although health professionals can give you an idea of what they mean, you must go straight to your doctor and discuss your laboratory result with him/her. He/she is familiar with your medical history, thereby, can give you better recommendation.