The reason why u cant get blood from a peripheral IV??


The reason why u cant get blood from a peripheral IV??


261 Posts

Specializes in Med onc, med, surg, now in ICU!.

Is this a homework question?

What are your thoughts about why you might not want to take blood from a peripheral IV? It's not that it is not possible, but it's not appropriate.

Think about why the IV was inserted, what you are using it for and how that use may affect any blood/tests performed on the blood taken from an IV.

jlmb214rn, BSN, RN

1 Article; 51 Posts

Specializes in Medical/Surgical.

It is totally possible (depending on the gauge, the vien, and the site) to obtain blood from a peripheral IV site. Infact, in our ER, the initial labs are usually obtained as the IV is started. Once a site has been established, you need to take several things into consideration before drawing labs from a peripheral site (or even a CVL, for that matter).

What fluids are going through the site? If you have K+ in the fluids and you are drawing a metabolic panel, the potassium level can be affected. Similarly, and even more common, PPN can effect the whole metabolic panel, as it is especially notorious for sticking to the walls of the angiocath.

Also to consider, what does the site look like?? If the site looks even a LITTLE pink, you could be getting false readings on a blood cluture or even WBC's.

Also, consider the gauge of the IV. Smaller gauge IV's can destroy cells in the blood and effect lab values. Lab will usually call you and tell you that the sample is hemolysed.

Consider also, the vien. Drawing from a good site can cause the vien to collapse from the backwards pressure and make the site go bad. If the patient has crap-for-veins, the lab may ask you to try and draw from the site. But do you really want to comprimise the IV??

Keep these things in mind... even with blood draws from a CVL!!

iluvivt, BSN, RN

2,773 Posts

Specializes in Infusion Nursing, Home Health Infusion. Has 32 years experience.

Generally speaking,once an IV is started and being used you do not want to use it for blood draws. First,it may compromise the site and increase the complication rate. Most peripherals do not draw well and then you would have to draw a discard which is not always easy ,and do you really want to put a tourniquet on and then have your site leaking all over the place. Secondly,if not done properly you may have erroneus lab values. It is OK to start an IV and before administering anything,obtain a sample. You do not really want to do this. It sounds good in theory,but in practice most of the time you can not get a good discard or draw and it is not the standard of care.

Daytonite, BSN, RN

4 Articles; 14,603 Posts

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.
The reason why u cant get blood from a peripheral IV??

  1. The IV may have been placed in a small vein with poor blood flow that is unsuitable for blood drawing and will result in hemolysis of the sample
  2. The pressure of aspirating may cause the vein to collapse thereby effectively blocking off the blood flow in the vein
  3. Fibrin may have formed along the distal end of the IV cannula which acts as a flap so that upon aspiration it effectively closes off the cannula so nothing can be drawn into it
  4. The inflammatory response may have already proceeded so that there is enough swelling of the vein that no blood can get up behind and around the cannula as it sits in the vein resulting in little to no blood being able to be withdrawn
  5. INS standards discourage the use of blood withdrawal from peripheral IVs that are being used for the infusion of fluids except at the time the IV device is inserted

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