A G6PD test measures the levels of glucose-6-phosphate dehydrogenase (G6PD), an enzyme in your blood. We require all patients to undergo this test before scheduling any drips, booster or pushes that contain large amounts of Vitamin C. Large amounts of Vitamin C is rarely life threatening but if not monitored it can lead to nausea and upset stomach. All guest must undergo the G6PD test before receiving anything with high levels of Vitamin C.