Before a fasting blood test, a patient may only consume water and must abstain from any other foods or liquids, according to Quest Diagnostics. Fasting is necessary before certain blood tests in order to obtain accurate ... More »

When fasting before a blood test, an individual is allowed to consume water and take usual medications unless instructed otherwise by the health care provider ordering the test. No other food or beverages should be consu... More »

Metabolic profiles often require fasting, according to Adams Memorial Hospital. Other fasting blood tests include glucose testing, the renal function panel, and the lipid profile. When fasting for these tests, patients a... More »

Unless specifically requested by a doctor, fasting is typically not required prior to a prostate-specific antigen, or PSA, blood test, according to Lab Tests Online. If fasting is required, patients must consume no food ... More »

According to Quest Diagnostics, a lipid or glucose tolerance test requires eight hours of fasting. Health care providers may have other recommendations, depending on the type of test. More »

Patients should fast for at least 12 hours before they have a fasting blood test, according to St. John Providence Health System. Not all blood tests require patients to fast, but those that do require that patients abst... More »

A patient fasting for blood tests may have water during his fast, according to Quest Diagnostics. It is advisable to drink a lot of water during the fast because it is harder for care providers to draw a patient's blood ... More »