Fasting Blood Results

Some blood tests require the patient to fast for 12 hours before blood samples are collected in the morning.

Fasting means that for twelve hours before your blood test, you must not eat or drink anything, except sips of water. This includes chewing gum.

Substances in tea, coffee or cola can affect some blood results, so even black coffee and sugar free (diet) drinks must be avoided. Likewise smoking must be avoided on the morning of the test.

Fasting Blood Tests are for the following:

Fasting glucose; oral glucose tolerance test; lipids, triglycerides, fasting cholesterol and cholesterol. fasting is not needed for screening or monitoring of cholesterol but may be recommended for diagnosis.

If you are diabetic: Fasting lipid results are rarely needed in diabetic patients. if you are diabetic DO NOT fast before this test, and do not stop taking, or change, your existing medication. This is unless you have been expressly advised by a qualified healthcare professional.

If you have medicine to take in the morning: You should not alter your medication unless instructed to do so by your doctor. If your medicine needs to be taken with food and this will interfere with the timing of your fasting blood test, please discuss this with your doctor.