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Getting Labs Drawn? A "You Need to Know"

Taking vitamins or supplements for the right reasons is usually not a big deal—but if your healthcare provider has ordered lab tests for you, keep in mind that your otherwise healthy practice can result in inaccurate results. And maybe even a misdiagnosis. For example, many people take biotin as a nutritional supplement. Biotin, also known as vitamin B7, is relatively harmless as a water-soluble vitamin, but it can cause significant interference with your lab results, particularly those tests for thyroid, and troponin levels that are tested following a heart attack.  

Vitamin B7 is a great example, so to make the point, let’s stick with it—because it holds true for lots of other supplements or vitamins. Biotin can be found in most over-the-counter daily prenatal and multivitamins, and as a supplement taken for hair, skin, and nail growth. It’s tricky. Despite what you know now about biotin or B7, it’s also called vitamin B8, vitamin H, or coenzyme R, so checking the bottle is very important. Biotin is often present in these preparations in amounts that will interfere with your lab results.  

Sounds like a catch-22. When your provider asks about your medications, always tell them about any vitamins and supplements you’re taking as well. Other popular supplements that may interfere with laboratory testing include creatine, Vitamin C, Vitamin E, B12 (folic acid), and Iron.  

Prepare. A lab appointment is typically easy. You just show up with little or no preparation. Are you one that gets light-headed, or never seems to have enough blood to spare? It’s best to be proactive and prepared by drinking plenty of plain water in the 24 hours before your appointment. Notify your phlebotomist if you have a concern of becoming faint with blood draws. These simple actions make the experience better for everyone—but mostly for you. 

Take your prescription medications. All of them—unless your provider tells you otherwise. In the case of vitamins and dietary and nutritional supplements, stop taking them at least 72 hours prior to your appointment. And in the case of pure biotin, stop taking it one week before you test. 

Fasting tests. Don’t eat or drink anything 8 hours prior to your appointment. The exceptions to this are plain water, black tea, black coffee, and your prescription medications. 

Wondering about a UTI. If you are taking AZO for symptoms of a urinary tract infection (UTI), stop taking it 24 hours before your appointment. If you’ve taken it before, you know it turns your urine neon orange. This intense color not only stains your clothing, but also interferes with the ability of your technician to run the preliminary urine test and may delay your diagnosis.  

It’s always good to be informed, especially when it comes to the mystery lingo in the medical world. No matter what type of appointment you’re preparing for, whether it’s a colonoscopy or a “simple” blood draw, be your own best advocate. Ask questions. It’s ok to be curious about your health. 

Anneliese Wilhelm, FNP-C 

ViaroCare 

For questions or comments, contact wellness@viarohealth.com