Listen up, ER nurses (or really any nurse that draws their own blood samples)! Let me paint a picture for you: you’re having a crazy hectic day running in and out of all of your patients’ rooms drawing blood, checking vitals, giving meds and putting out little fires all over the place. FINALLY, you sit down to catch up on some charting thinking all your tasks are caught up when the phone rings. It’s lab telling you that…say it with me now…your blood samples were hemolyzed!

Instantly, you want to scream at the lab tech, because OBVIOUSLY they left your samples sitting around for too long or they messed up somehow because that IV you placed DREW PERFECTLY and you sent the sample FOREVER ago. I get it and I’ve said that same line to lab techs before, however, I now know a little bit better. Even if I start the most beautiful 18 gage IV, there’s about a zillion land mines to avoid to provide a perfect blood sample that isn’t hemolyzed or clotted (because those are two different things!). And chemistry panels have to be spun down on a centrifuge prior to assessing if the sample is hemolyzed or not which takes around 10 minutes. So cool your jets and instead of yelling at a lab tech who likely had no part in your fudged up specimen, read on to find out all the ways you can help yourself not waste time (or rage) needing to recollect blood samples!

What’s the difference between hemolyzed and clotted samples?

Oh gosh, I’m so glad you asked because if you’re anything like me, I thought they were the same thing for far too long into my career. Clotting is when blood cells…form clots and stick together. I’m sorry I don’t have a better way to put that. This isn’t as common of an issue as you can generally see clots have formed in your blood tubing or syringe prior to ever sending it to lab. Also, the blood won’t transfer into your tubes without you forcing it which leads to hemolysis anyways so, double whammy, your sample is no good. Hemolysis on the other hand is the rupturing of red blood cells which is unidentifiable with the naked eye and often done completely inadvertently during a blood draw.

What causes blood specimens to clot?

1. Syringes have no anticoagulants in them so leaving blood in one too long can lead to clotting. Don’t let blood sit on a counter in the syringe for very long.
2. Slow blood draws into a syringe can allow enough time for the blood to clot as the coagulation process begins as soon as the draw starts.
3. Not inverting your tubes gently approximately 10 times after transferring blood into them. This helps make sure the anticoagulant in the tubes mixes thoroughly with the blood sample, hence, lowering the chances of it clotting.
   
   

Why do I care if the blood is hemolyzed?

You care because hemolysis causes certain analytes (substances being measured/tested) to be elevated due to red blood cells rupturing and leaking constituents. This often results in an elevated lactic acid level, potassium, magnesium, phosphorus, ammonia and BNP. Obviously patient care is dramatically effected if these numbers are falsely elevated and could even result in massive harm to patients if their false results are treated. If someone’s sample is hemolyzed and shows a very high potassium level, the provider may order medications to lower potassium levels which could end up making the patient’s TRUE potassium level way too low.

Does drawing blood through an IV catheter make a difference?

Absolutely!! Blood drawn through an IV catheter has a 20% hemolysis rate while blood drawn through a straight needle stick has a <1% hemolysis rate. The reason for this makes a ton of sense–catheters are designed to stay open under the positive pressure of medications or IV fluids being pushed through them, therefore, when faced with negative pressure from drawing blood, they can crimp and collapse which creates turbulence which then causes…hemolysis! Put simply, IV catheters aren’t meant to draw blood from so they don’t always work out well. Are we still going to draw blood from IV starts? Of course! Just realize the odds are already working against you.

What can I do to reduce my chances of hemolysis?

Pick the best site for your blood draw! The antecubital vein (that big ol’ vein in the crook of your arm) has been shown to reduce incidences of hemolysis when compared to distal sites!

Don’t leave a tourniquet on for more than 1 minute when possible

Always allow your site to dry thoroughly after cleansing it with alcohol — this is exactly how alcohol works to sanitize an area anyways!

When using a syringe, pull blood sample back slowly, even when you have a large bore IV that has the ability to draw blood faster. RESIST the urge as you’re causing too much turbulence!

Large volume syringes (like 20mL) are much more likely to result in clotting AND hemolysis so you’re better off to use two 10mL syringes instead.

This one surprised me! It is actually better to slowly and steadily draw blood back into a syringe than to use a Leur Lock Access Device (also called a vacutainer)! There is a 9% hemolysis rate when using syringes vs a 22% hemolysis rate with the access device. What?!

I already said it, but I’ll say it again: draw blood back SLOW and STEADY when using a syringe. Got it guys? SLOW….STEADY….

After you’ve pulled the blood back into a syringe, you need to get the sample into the blood tubes, right? We’ve got several routes to accomplish this– 1. using a blunt needle or 2. a transfer device. The best route to use is the transfer device and here’s why: blunt end needles are 18 gage and transfer device needles are 20 gage so it’s thought that blood enters the tubes with too much velocity through the blunt end needles and lysis occurs when the blood hits the bottom of the tubes with too much force.

On the same note, tilting the blood tubes as you transfer the samples into them will help prevent hemolysis by allowing the blood to flow down the sides of the tube instead of hitting the bottom.

Try to fill all the tubes to the max capacity they are suppose to hold. Partially filled tubes may contain too much excess additives which can cause hemolysis of the red blood cells.

GENTLY mix all tubes by inverting them approximately 10 times to thoroughly mix them with the additives in each tube.

If blood looks frothy, it means a connection site is loose. Tighten all connections and try again; if the blood is frothing, it will almost certainly be hemolyzed!

Being a nurse is really hard sometimes and having to do part of your job multiple times is incredibly frustrating! I hate feeling like I am not able to utilize my time most effectively which puts me in a terrible mood which, in turn, makes me far from the best nurse I can be. Knowing everything I can about drawing blood helps me to avoid redraws and, ultimately enjoy my job more. Plus working cohesively with all the ancillary departments in the hospital, including lab, helps to make everything run more smoothly for employees and patients alike.

Happy Poking!