GGTp Blood Test: Uses and Normal Levels Glutathione Index Fasting for blood work typically involves avoiding food and drink (except water) for eight to twelve hours to ensure accurate results, particularly for tests like glucose, cholesterol, and triglycerides. It is important Blood Plasma Quality Control by Plasma Glutathione Status Which Blood Tests Require Fasting Making bloodwork work: the impact of sample collection, processing, and storage on plasma glutathione measurement, and implications for translation Translational Psychiatry