Blood sample volumes: emerging trends in clinical practice and laboratory medicine.

Blood loss because of phlebotomy for diagnostic laboratory tests is a well-recognized risk to neonates, particularly low-birthweight infants. In contrast, the risk of anemia from blood drawing in adults is relatively poorly studied. A few clinical studies have demonstrated the magnitude of this issue for critical care patients; most adult patients can easily tolerate the loss of blood volumes typically used for laboratory tests. Recommendations for promoting blood conservation in adults who frequently are phlebotomized include using smaller collection tubes, but more importantly organizing blood draws to eliminate duplicate and other unnecessary test requests and consolidating multiple collections into as few as possible by scheduling them. Emerging trends in medicine that will bear on the practice of blood conservation are "bloodless surgery," standardization of collection tubes for laboratory automation systems, and smart laboratory information systems that provide instant feedback to ordering physicians.