Laboratory tests increasingly are used for patient care due to the large number of tests available and the short turnaround time due to automated laboratory instruments that make them easy to perform, as well as the need for objective data to support medical decisions. For many years it has been well known that blood loss from laboratory testing (BLLT) can be significant in hospitalized adults. Early studies report an average daily BLLT of 12.4 mL in general wards and 40 to 50 mL per day in intensive care units. (1-3) In a tertiary care teaching hospital, blood collected was, on average, 45 times the amount necessary for analysis. (4) In addition, a survey of 19 community and academic hospitals identified that blood collected for laboratory testing in adult patients was 2.5 to 10 times the amount collected for pediatric patients for the same tests, despite the fact that laboratories used the same or similar laboratory instruments. (5) Blood loss due to laboratory testing or may not lead to lower hemoglobin concentration, anemia, and increased transfusion requirements. (2-4,6) This situation continues to date. (7-10) Actual laboratory instruments use small amounts of sample, often in the range of 3 to 100 [micro]L, but it is common practice to draw full large-volume tubes, regardless of tests requested and amount of sample required. Our objective for this study was to reduce BLLT in hospitalized adults using small-volume tubes (SVTs) and to evaluate its impact in the analytical phase.