Several tests exist to check blood sugar levels. According to the National Institutes of Health, the standard fasting glucose test measures blood glucose levels after a fasting period of at least eight hours. The oral glucose tolerance test requires consuming a solution of glucose during the testing time frame. A random blood glucose test does not require fasting and is a reflection of recent meal intake, according to the National Institutes of Health. The hemoglobin A1c test measures blood sugar averages over the past two to three months and does not require fasting.
Step 1
Verify the type of glucose test ordered by your physician. The type of test will indicate whether or not a fasting period is necessary. Ask the physician or lab how many hours of fasting is indicated. If fasting is required, ask the physician about instructions for taking morning medications.
Step 2
Eat as usual during the days leading up to the evening before the appointment. Avoid significant changes in dietary patterns, which may affect the accuracy of test results.
Step 3
Plan for at least eight hours of fasting or more as indicated by the physician or lab. Fasting indicates nothing by mouth other than water. Non-fasting random glucose testing or hemoglobin A1c requires no further preparation.
Tips and Warnings
- As noted by the National Institutes of Health, the oral glucose tolerance test requires drinking a glucose solution after the initial blood draw. Labs will be drawn every 30 to 60 minutes after the initial blood draw up to three hours duration.
- According to the National Institutes of Health, a normal hemoglobin A1c level is less than 6 percent. Normal oral glucose tolerance levels differ based on the laboratory test and solution used. Contact your physician to discuss your results.
