Wisdom from the vets

a lot of supplements don't stay in your system very long, and I take them every day, so I didn't worry about those. I only take B12 every two weeks (a megadose), so I don't schedule labs right after I take that (or else if it's close, I'll wait 'til after the appt before taking it). I also held off on iron for a couple of days this last time because that's another one that builds up in your system, but then again, I take that one every day, too, so it might not matter.

As Grim said, sometimes it makes sense not to take them for a day or two before labs, but certainly not for any extended time. It doesn't hurt to miss a day or two of vitamins.

If you take a high dose of something once or twice a week (e.g., I take a large dose of Vit D twice a week, and take a large dose of B12 once a week), you probably DO want to skip the dose right before you have the lab work done. I once forgot that I was having blood drawn and took my B12 and Vit D the day before and the results were both high. We just rechecked them after 3 months once I explained to the Doctor what had happened.

Lora

The hematologist has me stop taking iron at least 4 days before a blood draw to avoid false readings.

I stop all other supplements 48 hours before.

This is the recommendation of my bariatric endocrinologist at the Cleveland Clinic.

WOW! Just checked back in. Awesome info from all of you! Thank-you so much for taking the time to reply