Dear Center for Phlebotomy Education:

I recently became aware that when our phlebotomists draw venous blood gases along with routine labs they use a regular 10-20 cc syringe. First they evacuate the syringe into whatever tubes are required for the routine labs with a safety transfer device, then they fill the blood gas syringe also using the transfer device. I do not think this is best practice, but am not able to find documentation to support my position. As a matter of fact, there is woefully little information regarding collection of venous blood gas specimens, their place in the order of draw, etc. What should we do?

My response:

You are right to be concerned about this practice. It does sound unorthodox and contrived.

If we understand you correctly, they must be forcing blood from the regular syringe, through the safety transfer device and into the blood gas syringe by pushing on the plunger of the regular syringe. The only way to accomplish this is for the interior needle of the safety transfer device to be inserted into the blood gas syringe, and the two syringes pushed forcefully together for a tight seal as the blood is pushed from one syringe to the other. The safety transfer device is not intended for that purpose. Because the connection between the blood gas syringe and the safety transfer device is dangerous and ineffective, it sounds like it's begging for a blood exposure.

The better approach would be to draw the blood with a butterfly set that has a clamp. After the puncture is performed, attach a small syringe to remove the air in the tubing. A 3 cc or 5 cc syringe would be fine, but even a TB syringe would suffice. After removing the air from the line, clamp it off, attach the ABG syringe, open the clamp and withdraw the sample. Then close the clamp, remove and cap the syringe, attach a regular syringe, open the clamp and complete the draw for the remaining tubes. A tube holder adapter could be added instead of the syringe to fill the tubes.

We've heard of phlebotomists drawing blood gases (venous and arterial) into heparinized tubes instead of blood gas syringes. Make sure your creative phlebotomists don't make this mistake, too. The heparin in tubes is not the proper formulation of heparin, and the vacuum in the tubes subjects the sample to subatmospheric pressure, which can alter results. 

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