Phlebotomy Tips: How to Avoid Hemolyzing Your Samples

Are you a phlebotomist, or interested in learning more about phlebotomy? If so, you’ve come to the right place. Getlabs Phlebotomy Tips is a series focused on sharing knowledge, advice, and best practices for phlebotomists and mobile phlebotomists.

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There’s a killer on the loose that’s responsible for nearly six times as many rejected blood samples as the next most common reason (insufficient sample volume). You’ve likely encountered this destroyer of samples yourself without realizing it. The tell-tale sign of this culprit? A tinge of red in the serum or plasma of the sample you collected.

We’re talking about hemolysis.

Derived from the word “Hemo”, meaning blood, and “lysis”, meaning destruction of cells, hemolysis is the most common reason for a rejected blood sample. It’s a massive time waster that can delay treatment, diagnosis, and, often, time-sensitive medical decisions. That’s why avoiding hemolysis in a blood sample is critically important.

Before we can dive into how to prevent hemolysis, we first need to understand how it occurs.

Let’s explore.

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What is hemolysis?

Red blood cells contain hemoglobin, an iron-rich protein that gives the cell its red color. Hemoglobin is passionate about three things: oxygen, carbon dioxide, and transporting those two molecules where they need to be. When red blood cells pass through the lungs, it clings to oxygen molecules and delivers them into the tissues throughout the body for cellular functions. At the same time, it also transports carbon dioxide back to the lungs so it can be removed from the body.

When red blood cells rupture, they spill their contents (namely, hemoglobin) into the liquid portion of the blood. If this rupture occurs during specimen collection, then the blood being tested is no longer the same as the blood circulating in the patient.

To paraphrase Star Wars a bit, “This is not the specimen you’re looking for.”

Why? Red blood cells contain 23 times as much potassium as the liquid portion of the blood. When red blood cells rupture during collection, the specimen being tested is now saturated with potassium. With that much potassium, if the sample is tested and reported, it may just send the physician into a frenzy and create a lose-lose situation for the patient.

The result could lead the physician to prescribe treatments or medicine that can be ultimately unfavorable to the patient and their health. Or, if the patient actually has low levels of potassium, the tainted sample may send test results into a normal range. This could lead to inaction on the part of the physician when action is required.

However, it’s not just potassium that hemolysis affects. Tests like LDH, AST, ALT, phosphorus, and magnesium also exist in red blood cells in higher concentrations. In fact, hemolysis can impact almost every test because hemoglobin is a liquid protein, which dilutes the serum or plasma being tested. With more hemolysis, comes more dilution.

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It’s clear that hemolysis is all-around bad news for any testing sample. Fortunately, there are several helpful tips that can help minimize hemolysis when collecting lab samples. Here are a few best practices to implement to avoid these seven top causes.

7 best practices to minimize hemolysis

1. Avoid line draws

IV devices are notorious for hemolyzing red blood cells. You should perform a venipuncture instead.

2. Avoid vigorous mixing

Treat the sample like it’s full of fragile crystals; if you shake it too hard can it fracture the cells and ruin the sample.

3. Avoid excessive pulling pressure when using syringes

Withdrawing the plunger from a syringe shouldn’t be a game of tug-of-war. The excessive turbulence will cause the red blood cells to burst and should be avoided.

4. Don't rim clots

Rimming clots to remove fibrin might be tempting, but this can inadvertently rupture red blood cells at the same time.

5. Position the needle properly

If the needle is partially occluded by the vein wall then the chances of hemolysis increases. Make sure to position the needle properly and avoid this easy-to-avoid mistake.

6. Pre-warm skin puncture sites

Squeezing the tissue near a skin-puncture site can cause hemolyze red blood cells. Prewarm the puncture site to reduce the need to squeeze excessively.

7. Fill tubes fully

Anticoagulants can be hard on red blood cells, especially if the concentration is too high. Filling the tubes fully will ensure the concentration doesn’t overwhelm the fragile cells.

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Remember, accurate test results start with the collector. These best practices will help ensure blood samples are in the best position to provide reliable results and prevent misdiagnosis, postponing treatment, or delaying time-sensitive medical decisions because of hemolysis.

As always, thanks for stopping by! We look forward to sharing more phlebotomy tips and best practices with you in the future.

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If you share our values and our enthusiasm for helping our patients have the best experience, we have a home for you at Getlabs.

Check out our careers page and find out if we’re hiring in your area!