FBS Blood Test and Fasting Durations..

[Johhny]

Hello Everybody,

Does fasting for 13 to 14 hrs before Fasting Blood Sugar test gives incorrect result ?
If yes, then how much the BG level will, higher or on lower side ?


Thanks in advance..

 

[bulkbiker]

There isn't an "incorrect result" really... the test will simply give your level at that time.
I found that the longer I fast the lower the blood sugar goes until about the third day when it starts to go back up.

 

[bulkbiker]

Hello Everybody,

Does fasting for 13 to 14 hrs before Fasting Blood Sugar test gives incorrect result ?
If yes, then how much the BG level will, higher or on lower side ?


Thanks in advance..

Sorry just saw it was your first post so hi and welcome.
Do you want to give us a bit more info about yourself?

 

[angustia]

Somebody gave a link a while back - can't recall where - and it says that non-diabetic reading for fasting is between 4.0 - 6.0 mmol.

 

[Brunneria]

Hello Everybody,

Does fasting for 13 to 14 hrs before Fasting Blood Sugar test gives incorrect result ?
If yes, then how much the BG level will, higher or on lower side ?


Thanks in advance..

Hi and welcome Johhny

As BB says, a fasting bg test is just a snapshot of your bg at the time the test was taken.
Blood glucose tends to rise and fall a bit during the day and night, even if you don't eat anything at all, so a single fasting blood glucose test doesn't tell you anything except whether your blood glucose was high, low or in the middle.

It is then up to the healthcare professional to interpret the results and decide whether to investigate further.

Sometimes we are asked to fast before blood tests because they are cholesterol tests, or fasting blood glucose, but an HbA1c test is may be taken at the same time. The HBA1c test provides an average(ish) reading of what your blood glucose has been over the last 2-3 months, and it doesn't matter whether you fast or not for it.