Published
Hi all, I'm an NTC in training and have experience in Integrative Oncology (but am not a nurse or phlebotomist) - and am still learning the ropes, especially when it comes to labs and proper procedures. Through my studies, I've now learned that there is an "Order of Draw" for lab work - probably common knowledge in this community, but new to me!
That has led me to this, "Oh sheesh" personal moment - and I hope you don't mind this personal question?
A family member (following a cancer diagnosis that she's now in remission from) gets about 40 lab tests every six months from Quest Labs. One of those is Plasma VEGF. Several rounds of tests ago, her doctor suggested she get VEGF drawn "first" by the phlebotomist because apparently VEGF levels can be impacted if it's closer to the last tube of blood drawn. So, for the past several rounds of labs, we've requested VEGF Plasma to be drawn first, and then proceed as normal. Our phlebotomist has never mentioned it at the lab, or voiced concern with it.
However, as mentioned, I just realized there's something called an "order of draw"... so now my concern is that we've somehow contaminated other tubes of blood by requesting VEGF to be drawn first (which I believe is a lavender top tube)?
I've since read extensively online about whether or not "order of draw" is truly important, and have found several articles that say that while it's good practice (and if you can, "why not do it"?), contamination risk is extremely minute and inconsequential. And that "order of draw" was initially established many years ago on a small sample group, and has since been shown to be inconsequential (though still encouraged simply because the extra precautions are never a bad thing). Especially if a "closed loop" system of drawing blood is in place?
I know you can't say for certain, but I'm wondering if you could help me understand in generalities:
a) We use Quest Labs - I'm assuming they would naturally use a "closed loop" system in terms of drawing blood? I'm not sure sure what "closed loop" means (still learning), but gather that this is always best practice, so imagine major labs like Quest or LabCorp would use this methodology?
b) In your opinion, is the risk of contamination extremely small in a "closed loop system"?
c) If we requested VEGF Plasma to be drawn first, do you know if there are phlebotomy practice measures in place to prevent contamination? In other words, since our phlebotomist didn't "bat an eye" by the request (and it's been three lab draws over the past 1.5 years), does that mean it's likely that the phlebotomist was aware of the "order of draw", was able to draw VEGF Plasma first per request, and then naturally took measures to avoid contamination because such precautionary systems are in place?
I know nobody here is psychic (smiles!), and you cannot say for certain whether contamination took place. I guess I'm just looking for your general comments here, for my own peace of mind and thought processing.
Thank you very much in advance!