Obtaining blood samples from peripheral intravenous catheters: best practice?

Occasionally, nurses perform phlebotomy via intravenous catheters, especially to improve efficiency in short-stay or procedural units. The intent of this practice is to reduce the number of venipunctures and thus increase patients’ comfort. However, obtaining laboratory specimens from peripheral intravenous catheters may hemolyze the specimens, and can even dislodge catheters and necessitate restarts. Both of these scenarios may lead to multiple needle sticks and delayed treatment, not only reducing patients’ satisfaction but also increasing costs of care. Hemolysis is a rupture of red blood cells with a release of hemoglobin and other intracellular contents into the plasma. In vitro hemolysis interferes with tests such as blood bank/coagulation testing and measurement of levels of creatine kinase, lactate dehydrogenase, potassium, iron, digoxin, alanine and aspartate aminotransferase, and β-human chrorionic gonado tropin. Depending on the level of hemolysis, specimens may need to be rejected and another sample would need to be collected. Overall, hemolyzed specimens account for nearly 60% of rejected specimens. Factors that contribute to hemolysis vary from anatomical and physiological characteristics to equipment and techniques used during phlebotomy. According to the American Society for Clinical Pathology, a 2% hemolysis rate is considered best practice. In this review, we synthesize available evidence about the effect of collecting blood samples for laboratory tests from peripheral intravenous catheters on hemolysis rates in the specimens. A regular feature of the American Journal of Critical Care, Clinical Evidence Review unveils available scientific evidence to answer questions faced in contemporary clinical practice. It is intended to support, refute, or shed light on health care practices where little evidence exists. To send an eLetter or to contribute to an online discussion about this article, visit www.ajcconline.org and click “Respond to This Article” on either the full-text or PDF view of the article. We welcome letters regarding this feature and encourage the submission of questions for future review.