Drawing blood from a peripheral IV

[BoardingDoc]

So the general rule of thumb that I've encountered has been that you may use an IV to draw blood on initial insertion, however, once that line is established, it may no longer be used for blood draws. My question is: why? I haven't exhaustively researched this subject, but the few studies that I've dug up seem to indicate that there is no significant difference in either hemolysis or bacterial contamination when comparing blood drawn from an established peripheral IV vs fresh venous access.

Am I missing something, or does this policy not make sense?

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[deleted547339]

Whoever told you that is wrong. You can use a PIV for blood draws whenever. It's not ideal for a blood culture if it's an old PIV, but you can totally use a PIV for blood as long as you waste.

 

[Rendar5]

So the general rule of thumb that I've encountered has been that you may use an IV to draw blood on initial insertion, however, once that line is established, it may no longer be used for blood draws. My question is: why? I haven't exhaustively researched this subject, but the few studies that I've dug up seem to indicate that there is no significant difference in either hemolysis or bacterial contamination when comparing blood drawn from an established peripheral IV vs fresh venous access.

Am I missing something, or does this policy not make sense?

The policy is stupid, but it exists at a lot of hospitals. The probable reason is that there may be an unclear amount of contaminant saline in the flushed line. Still, you can always draw off 10 cc's of blood as waste before doing your actual draw.

 

[DeadCactus]

Seems to negate one of the major benefits of placing a line...

 

[RustedFox]

Dumb rule.

Dumb.

 

[deleted109597]

Stupid rule, but nearly universal. Probably a union/staffing rule. Techs can't draw from IVs, nurses too busy, etc.

 

[gutonc]

Stupid rule, but nearly universal. Probably a union/staffing rule. Techs can't draw from IVs, nurses too busy, etc.

This is the real issue. Only RNs and above are allowed to touch "vascular access" so if they're going to draw from an IV, an RN has to do it. Which is fine when putting it in, but a waste of resources (RNs are expensive, phlebot/techs are cheap) when you just need a blood draw. So to avoid the issue, somebody makes a "rule" and there you go.

 

[EM2BE]

I have only been a few places where this is a "rule." I have written orders to say it was okay for labs to be drawn from IV. The nurses thanked me for it.

 

[gman33]

The places I work, they draw labs off the lines all the time.
I spend a lot of time working in an ICU.
I couldn't even imagine having to stick the patients that many times.

If you get weird results, talk to the nurse about how the labs were drawn.
Sometimes you will get a diluted sample. Send a repeat if in doubt.

 

[Dexterosa]

Hi, I started work as an RN recently, and I will be working in the night shift, where we will have to do our own blood draws... I did not get so far any special training for that. I mean, I know the theory how to do it, but .. practical experience is another story, so I was thinking why not to draw the blood from IV... however I did not see anyone doing it... it is done from Centrals, pic lines... etc, yes it is policy - not to use IV. So I started looking for any source. (My reason is that I do not want to poke patient few times and torture him, then twenty minutes later receive new order about additional blood work to be drawn... do it all over again, and morning values are going to be funny... so hurray, let's redraw... when there is an easy way... flush IV, draw back, throw it out, and flush it again, reconnect and let go...
IV supposed to be changed every 3 days... might be slightly different hospital by hospital, and so on. So yes, I would be thankful too, to any MD, who would kindly make my and patients life easier and write order, specifying that blood could be drawn from IV.

 

[dotcb]

We draw blood from PIV's all the time. Just need to waste or aspirate to get rid of the saline in the tubing.

 

[deleted109597]

We draw blood from PIV's all the time. Just need to waste or aspirate to get rid of the saline in the tubing.

You don't need to waste it. You can autotransfuse it back.

 

[wholeheartedly]

I work in a clinical lab and our institution allows this. The problem is we run into a significant number of samples contaminated by whatever was in the line. They always say they drew enough waste, stopped the infusion, or whatever, but it still happens a lot (we track it) and results in a lot of redraws and delays in getting accurate results out. I think they get rushed and shortcut a bit sometimes.

 

[Bostonredsox]

The places I work, they draw labs off the lines all the time.
I spend a lot of time working in an ICU.
I couldn't even imagine having to stick the patients that many times.

If you get weird results, talk to the nurse about how the labs were drawn.
Sometimes you will get a diluted sample. Send a repeat if in doubt.

At our place the MICU nurses draw all labs off the triple Lumens. But if pt doesn't have a CVC, just peripherals, phlebotomy has to come and stick them. It's annoying and dumb.

 

[ScienceMakesMe=-O]

The reason they do not want you drawing from an IV once the line is established is because they are trying to minimize IV contamination as much as possible. By IV contamination I do not mean that you may be contaminating the IV site. IV fluid can easily contaminate blood draws (i.e. It can dilute out chemistry analytes and falsely decrease them, for example). Just think...if you draw a specimen from an IV line where something like a parenteral solution is being given to the patient, it could get into the labs and for lack of a better term, completely screw up the results. The medical technologist will probably recognize this and ask for a redraw...Therefore, if you are going to draw from an IV line you must shut it off for at least 10 minutes to allow any IV fluid to dissipate AND draw a discard tube of approx. 10ml.

 

[Hamhock]

Has anyone seen increased rates of hemolysis from PIV "blood draws"?

During residency we were shown pretty convincing data showing blood drawn from IVs had >>>>hemolysis....and this was at our county hospital and required the hiring of many more employes (techs) for peripheral sticks. I had never seen such hiring for any other reason, so I suspect there was some legitimacy to it; although I have always wondering if it was just the vaccuum-based technique most of us (the residents) were using to pull the blood from the hub of freshly placed IVs.

HH

 

[Doctor Bob]

Has anyone seen increased rates of hemolysis from PIV "blood draws"?

During residency we were shown pretty convincing data showing blood drawn from IVs had >>>>hemolysis....and this was at our county hospital and required the hiring of many more employes (techs) for peripheral sticks. I had never seen such hiring for any other reason, so I suspect there was some legitimacy to it; although I have always wondering if it was just the vaccuum-based technique most of us (the residents) were using to pull the blood from the hub of freshly placed IVs.

What I see a lot of are IV starts go through and through a vein, then as the large hematoma forms the techs try pulling blood from the lock (really just aspirating the hematoma) and yanking the plunger all the way back. The scant few ml's of blood get exposed to the high negative pressure in the syringe and the sample invariably comes back clotted (because it was drawn from a hematoma) or hemolyzed (because of the hard negative pressure).

If it's a good line and they don't try to pull the blood out too fast the hemolysis rate is pretty low. But that's just anecdotal.

 

[MSmentor018]

yeah it's just job security and historical hospital inaccuracy. some old codger writes it in the books then tells the next supervisor who tells the next and so on. i was a medic for 5 yrs, RN for 10 yrs before this career and have drawn more blood than Dracula with prader-willii. I remember the days when we taped down 25ga butterflys needles for infusion then took blood. it's standard in the PICU to pull out of a 24ga or drip it into a pedi tube. do a waste, small syringe (even 1cc tb if needed), gently pull back. supposedly keeping the tourniquet on >2min causes hemolysis. not sure if that's BS or not

 

[deleted547339]

have drawn more blood than Dracula with prader-willii.

Nothing to add, just thought this was worth quoting