--- title: "Why You Need a G6PD Test Before a High-Dose Vitamin C IV" url: https://icryo-stjohns-fl.com/blog/g6pd-test-vitamin-c-iv description: "High-dose IV vitamin C can be dangerous for people with G6PD deficiency. Learn what G6PD is, how the test works and what to expect in St. Johns, FL." lang: en --- Get Your Free Wellness Plan – Personalized just for you (https://icryo-stjohns-fl.com/free-wellness-plan) # Why You Need a G6PD Test Before a High-Dose Vitamin C IV Updated October 20, 2026 · 2 min read Image: G6PD blood test before a high-dose vitamin C IV at iCRYO St. Johns (https://icryo-stjohns-fl.com/__l5e/assets-v1/cf382d36-2e72-4e82-a209-7e637047607b/g6pd-test-vitamin-c-iv-st-johns-fl.webp) Before your first High-C IV, we'll ask for a blood test called a **G6PD screening**. If you've never heard of it, you're not alone. Here's what G6PD is, why it matters and what to expect. New to High-C? Start with What Is a High-Dose Vitamin C IV? (https://icryo-stjohns-fl.com/blog/what-is-high-dose-vitamin-c-iv) ## What Is G6PD? G6PD stands for **glucose-6-phosphate dehydrogenase**. It's an enzyme that helps protect your red blood cells from oxidative damage. ## What Is G6PD Deficiency? G6PD deficiency is an inherited condition in which the body doesn't make enough of this enzyme. It's one of the most common enzyme deficiencies worldwide. Many people with G6PD deficiency have no symptoms and don't know they have it until they're exposed to certain triggers, which can include specific medications, certain foods and high doses of IV vitamin C. ## Why It Matters for High-Dose Vitamin C At high doses, IV vitamin C can create oxidative stress in red blood cells. In people with G6PD deficiency, red blood cells can't protect themselves well and may break down. This is called **hemolysis**, and it can be serious. That's why responsible clinics require a G6PD test before high-dose vitamin C infusions. ## What to Expect 1. **A simple blood draw** 2. **Lab processing**, so plan ahead 3. **Results review** with our team 4. **Your first High-C IV** once you're cleared **Tip:** Schedule your G6PD test ahead of time so you're ready when you want your first infusion, especially before cold and flu season. ## What If I'm G6PD Deficient? If your test shows a deficiency, high-dose vitamin C IVs aren't safe for you. But you still have options. Our team may recommend: - A standard IV infusion (https://icryo-stjohns-fl.com/services/iv-infusion) appropriate for you - IM vitamin shots: https://icryo-stjohns-fl.com/services/im-shots - Other wellness services that fit your goals We'll also recommend you share your results with your doctor, since G6PD deficiency can affect other medications. ## Other Safety Checks Besides G6PD, our medical team also asks about: - Kidney stones or kidney disease - Iron overload conditions - Pregnancy or breastfeeding - Current medications ## Safety Is Part of the Service At iCRYO St. Johns, screening isn't a hurdle. It's how we make sure your treatment is safe. Learn about the benefits you're working toward in High-Dose Vitamin C IV Benefits (https://icryo-stjohns-fl.com/blog/high-dose-vitamin-c-iv-benefits). Ready to get screened? ## High-Dose Vitamin C IV in St. Johns, FL iCRYO St. Johns is at **120 Durbin Pavilion Dr Suite 103, St. Johns, FL 32259**, in Durbin Pavilion with free on-site parking. We welcome clients from Fruit Cove, Julington Creek, Nocatee, Ponte Vedra, World Golf Village and St. Augustine. - See our current intro offers: https://icryo-stjohns-fl.com/deals - Book your intro visit: https://icryo-stjohns-fl.com/book-now - Get your free personalized wellness plan: https://icryo-stjohns-fl.com/free-wellness-plan Questions? Call (904) 513-8877. ## High-Dose Vitamin C IV FAQs What is G6PD? G6PD (glucose-6-phosphate dehydrogenase) is an enzyme that helps protect red blood cells from oxidative damage. Why does G6PD matter for vitamin C IVs? In people with G6PD deficiency, high-dose IV vitamin C can trigger hemolysis, the breakdown of red blood cells, which can be serious. How is the G6PD test done? It's a simple blood test. Our team will explain the process and timing. Do I need a G6PD test every time? Typically, a G6PD test is done once before your first high-dose infusion. Our team will let you know. iCRYO St. Johns Team The iCRYO St. Johns team helps clients across St. Johns County look and feel their best. ## Related Articles What Is a High-Dose Vitamin C IV? A High-C IV delivers vitamin C directly into your bloodstream at levels you can't reach with pills. Learn how it works and who it's for in St. Johns, FL. https://icryo-stjohns-fl.com/blog/what-is-high-dose-vitamin-c-iv High-Dose Vitamin C IV Benefits High-dose vitamin C IVs support immune health, antioxidant protection and collagen. See the benefits, research and who it's for in St. Johns, FL. https://icryo-stjohns-fl.com/blog/high-dose-vitamin-c-iv-benefits IV Vitamin C vs. Oral Vitamin C: What's the Difference? Your gut limits how much vitamin C you absorb from pills. IV vitamin C bypasses that limit. Compare absorption, blood levels and when each makes sense. https://icryo-stjohns-fl.com/blog/iv-vitamin-c-vs-oral Learn more about High-Dose Vitamin C IV in St. Johns, FL View the High-Dose Vitamin C IV service page → https://icryo-stjohns-fl.com/services/high-dose-vitamin-c Start your wellness journey in St. Johns Get Your Free Wellness Plan: https://icryo-stjohns-fl.com/free-wellness-plan Book Your Intro: https://icryo-stjohns-fl.com/book-now (904) 513-8877 (+19045138877) ## Structured data ```json [ [ { "@context": "https://schema.org", "@type": "BlogPosting", "headline": "Why You Need a G6PD Test Before a High-Dose Vitamin C IV", "description": "High-dose IV vitamin C can be dangerous for people with G6PD deficiency. 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