Popping off top from lab tube when drawing labs

[pattykolo888]

I am brand new to nursing. I am working at a hospital that utilizes an IV team. I was taking care of a patient that was on a heparin gtt that needed a PTT lab drawn. She was a hard stick so we had IV team come and draw from the line. I was watching the IV RN use a 3 ml syringe to draw back blood from the line, popped off the top of the lab tube and then proceeded to squirt in the blood. Is this acceptable? Have other nurses seen or do this as well? To me, it just seems like the results may be skewed.

[Loracs72]

In peds, we do this all the time because the little veins can't handle the pressure of the tube suction. So we draw blood with 3 ml syringes and do one of three things - do exactly what she did and take the top off, take a needles and poke the top (which like somebody else says, risks you sticking yourself), or put it in the tiny pedi tubes that require the tops to be taken off anyways. As far as the blue tops, taking the tube off wont really skew the results as long as the right ratio of blood is used (which thats the only one that matters, anyways). Hope that helps.

I have and also staff that I have worked with have had to do this if we don't get enough blood for a Blue top, because the lab will call and say they don't have enough blood.

[DeeAngel]

I am far more concerned with someone using that small a capacity syringe to draw from a central line! We were taught to never use anything smaller than a 10 cc syringe on a central line.

[quazar]

The only time I see this technique used is in the NICU or at delivery when the doc drains the umbilical cord to get a cord blood sample. Lots of docs will just pop the top off the tube and let the cord blood drain into the tube rather than have the nurse draw it up. If I'm having that much trouble getting a sample off a patient, I call the lab.

[WinterSoldier]

Ex-phlebotomist/lab assistant and new RN here!

Short answer: It depends on the test (e.g. ionized calcium cannot be opened).

However, for most common tests opening up the tube will not change the results. The tubes are open when they are in the "analyzer" machines (chemistry, hematology, etc.).

If you aren't sure, check with your lab. What is important regarding the blue top sodium citrate tubes used for coag studies (PT, PTT, DDimer) is that they are filled within the range of the marker arrow– seen near the top of the actual tube– to ensure the ratio of additive to blood is correct. Blue tubes that are not filled properly will skew results and the lab will likely reject the specimen.

[brillohead, ADN, RN]

We can only draw off a *fresh* IV for labs (as in, standing there while it was inserted and nothing has been put into it yet).

We can draw off a PICC -- we flush, waste 10mL, then draw up whatever the lab needs into a syringe, then flush again. The phlebotomist then puts a blunt needle on it to transfer into the necessary tubes. (Only nursing is allowed to draw off a PICC at my facility, not the lab, so they have to come get us to do it for them.)

[kiszi, RN]

I was always told we can't draw from an IV site as they usually hemolyze the sample. Is there a time or instance when this is ok? (New nurse with 10 months experience only who is truly curious.)

My charge had me do it once to show me. When spinning the blood in a tiger top gel tube, the blood cells didn't fully separate from the serum like it should have because they hemolyzed when coming through the IV cannula. The serum was pinkish instead of the normal yellowish color.

The main reason for hemolysis is from pulling back too hard/fast. Happens with PICCs too.

If a line doesn't draw easily, I will go ahead and stick. When I have a patient without a central line I will usually get an 18 or larger in the antecub for blood draws, and my samples rarely hemolyze.

[marienm, RN, CCRN]

Twice I've had a burn patient come in who is so hemoconcentrated (Hct > 55) that the standard light-blue coag tube won't work...not enough citrate, I guess. The lab pops the top off a tube for us, puts in the right amount of citrate, tapes the tube shut, and sends it to us with a reminder that there's no vacuum in the tube anymore. I think we had central lines in both pts when this occurred, so we drew from the line with a syringe and then used a transfer device to connect the tube to the syringe and just gently pushed it into the tube up to the line. Since we have transfer devices (both the kind that go from male-luer-lock (ie: the end of a syringe) and female (ie: you can poke it into the end of a clave or a stopcock) to shielded-tube-filling-needle), I don't foresee a circumstance where I'd use a plain needle to fill the tube.

[ThePsychWhisperer, BSN, MSN, APRN, NP]

It isn't the best way but sometimes you've gotta do what you've gotta do. On pedi patients and billion year old ladies I have sometimes popped the top off a blue tube and let the butterfly tubing literally back drip into it when I couldn't get it to draw with a syringe. It works. It's slow but in a pinch it does work. There is a special tape (I forget what it's called)that you can secure the lids back on with. And of course these should be hand carried to the lab and the staff notified that the vacuum has been breached so they don't have an exposure incident. I only advocate this as an absolutely last resort and I'm sure someone will come along soon and tell me I'm The. Worst. Nurse. Ever!

I've had to do this with IV drug users with an extensive past, often with an IV catheter that won't feed properly and is hanging from the vein by a prayer. I have had to use this technique more times than I am proud of to get an entire rainbow on this population. But it comes down to the fact that sometimes you do what you have to.

[ThePsychWhisperer, BSN, MSN, APRN, NP]

I was always told we can't draw from an IV site as they usually hemolyze the sample. Is there a time or instance when this is ok? (New nurse with 10 months experience only who is truly curious.)

My charge had me do it once to show me. When spinning the blood in a tiger top gel tube, the blood cells didn't fully separate from the serum like it should have because they hemolyzed when coming through the IV cannula. The serum was pinkish instead of the normal yellowish color.

While this is not best practice (drawing from IVs), I draw from IV catheters a lot in the ED, especially if they're peds or little elderlies. I always draw my initial labs from a freshly inserted IV catheter, and cap all my IVs with Curo caps to prevent contamination with further draws. As long as the blood flows freely through the line without any kind of force, the blood sample should be okay. I have been practicing for four years and to this day have never had a blood sample to become hemolyzed doing it this way.

[bgxyrnf, MSN, RN]

I was always told we can't draw from an IV site as they usually hemolyze the sample. Is there a time or instance when this is ok? (New nurse with 10 months experience only who is truly curious.)

Perfectly fine... I do it all the time, both in the ED and in the ICUs.

If there are meds/fluids infusing distal to the site then they must be paused for a few minutes prior to the draw in order not to contaminate the specimen.

Additionally, a few mL of blood must be aspirated and wasted prior to drawing.

During the actual draw, I generally use a syringe but sometimes will use a transfer device. I'm just careful not to exert much force on the plunger while I'm drawing so that I don't hemolyze the specimen.

[Julius Seizure]

Ex-phlebotomist/lab assistant and new RN here!

Short answer: It depends on the test (e.g. ionized calcium cannot be opened).

Question for the expert!

We send i-cals in heparin blood gas syringes, not test tubes.....now those obviously are "open", as we draw directly into them. What is it about that test that makes that test tube un-openable, and why is the heparin syringe okay then?