Drawing blood from IV line policies

[Emergent, RN]

I just finished a covid 19 crisis nurse short-term contract in an ER. At this ER we were expected to draw Labs from pre-existing IVs.

At the last places I've worked that was a no no. We could only draw from Central lines. Lab would be called to poke the patient again for a lab draw.

What is the rationale one way or another?

[LibraNurse27, BSN, RN]

I have asked about this at my job, where we don't have a clear policy. Some pts have saline locked 18G IVs with great bloodflow. Some pts are hard sticks so we try to put in IVs in larger, deeper veins w/ US and draw from them as long as they have blood return. We have new IVs called "extended dwell peripheral IVs" that PICC nurses can place. It's like a PICC but in a peripheral vein and you can usually draw blood from them.

Lab is happy to let us draw from an IV. They advised us to pause the IV fluids/meds for 10 mins if drawing from IV w/ something running. Some drips can't be paused so then we can only do IV draw if we have 2 IVs. They say it won't affect the results because the blood is coming from a vein, as long as nothing was recently infusing through it. We draw same as from a PICC: flush, flush, draw waste, draw blood, double flush. I've never gotten weird results, only when someone didn't pause a banana bag and drew BMP from the IV... everything was off. But we paused it and labs came back normal.

I asked some doctors, all say they're fine with it but don't know much about how it might affect results. Seems like stuff like trops, CBC (unless blood running), PT/INR shouldn't be affected. Maybe BMP if they're getting fluids but seems OK when fluids paused. MDs recommended peripheral sticks for stuff like Vanco troughs and aptt when pt on heparin drip. In a pinch we have gotten order to pause a heparin drip and draw from the IV because no one could get blood. That made me nervous but result seemed accurate.

PICC nurse said it's fine but some risk of collapsing a vein if drawing frequently. She advised don't draw from 24/22 (if they even give back blood) unless emergent, and always double flush with push pause technique to break up any possible clots, and clamp the IV after if it's saline locked. But we still have no policy! So honestly if I think of it and they have an IV that draws I'll just do it since everyone I talked to is OK w/ it. Lab is happy, pt is happy! Sorry for long answer, this is something I've been looking into! Preserve those veins LOL