In an effort to reduce the quantity of blood drawn from a patient for pH and arterial blood gas determinations, we developed the Dade Arterial Micro Collection Set. This set contains a device for collecting 200 μl of blood for reliable blood gas and pH analyses. Using tonometered blood, we conducted a study at American Dade to validate the Micro Collection Device by evaluating its storage ability and by comparing its performance with that of a glass syringe. Results of this study show that a blood sample can be properly stored in the Micro Collection Device for 1 hour with no significant change in the pH or blood gas values and that the performance of the Micro Collection Device is comparable to that of the conventional glass syringe.