Is mixing of blood gas syringes after collection really necessary?

Because there is no evidence that this practice is carefully followed by all health care workers responsible for blood collection, especially outside the laboratory boundaries where most blood gas analyzer are installed, we planned this study to investigate whether mixing the blood gas syringe immediately after collection would be really necessary. Under the specific experimental conditions of this study (i.e., collection of venous blood so as not to injure the patient with an arterial puncture, blood gas analysis performed immediately after drawing blood), our results indicate that avoidance to immediately mix the blood gas syringe after collection does not appear to be a cause of clinically significant bias in blood gas analysis. We could only observe a modest variation of Glu and Lac, showing an opposite trend. This is probably due to initial Glu consumption by blood cells in the unmixed sample, which is accompanied by generation of Lac. Thus, further studies would be needed to assess whether leaving blood gas syringes unmixed for longer time may cause a more evident bias.