y the use of heparin in preparing samples for blood - gas analysis

16 October 2007 ■ MLO www.mlo-online.com T he significance of good practice during the pre-testing phase of clinical-laboratory investigation cannot be overemphasized. The production of high-quality, accurate results, which are clinically useful, depends as much on practice before the patient’s sample reaches the laboratory as it does on the analytical phase within the laboratory. There are few tests that better exemplify this general truth than blood-gas analysis. Less than scrupulous adherence to protocol for blood collection, as well as that for the handling and timely transport of specimens, can invalidate blood-gas results. This article addresses one aspect of the pre-testing phase of blood-gas analysis: the use of heparin to anticoagulate blood samples. The main focus will be the potential errors in measurement of blood-gas analyzer parameters that can arise as a result of the necessary addition of heparin to blood, and how these can be avoided or at least minimized. The article begins with a brief overview of heparin itself.