Very good afternoon doctors. i need to take a fasting blood test for glucose and for cholesterol. how many hours should i be on a fast before the blood test? what time the next day, morning or afternoon, is a good time to get the blood test?

Take the test every morning before breakfast. This will give you an average result over time. Eating a late dinner, reading will be higher than eating an early dinner. In a prior question you asked why you had frequent nocturnal urination, yet stated you were not diabetic. High sugar levels and a1c may be the reason for your need to urinate throughout the night.

The fasting time lipids is at least 9 hours. 8 hours is sufficient for glucose only.